WEBVTT

00:00:00.000 --> 00:00:01.980 align:middle line:90%
[SQUEAKING]

00:00:01.980 --> 00:00:03.960 align:middle line:90%
[RUSTLING]

00:00:03.960 --> 00:00:07.920 align:middle line:90%
[CLICKING]

00:00:07.920 --> 00:00:16.088 align:middle line:90%


00:00:16.088 --> 00:00:17.630 align:middle line:84%
RICARDO CABALLERO:
Today, we're going

00:00:17.630 --> 00:00:22.080 align:middle line:84%
to talk about a very
important topic in economics,

00:00:22.080 --> 00:00:23.390 align:middle line:90%
which is expectations.

00:00:23.390 --> 00:00:25.490 align:middle line:84%
We have barely
mentioned expectations

00:00:25.490 --> 00:00:27.200 align:middle line:84%
when we talk about
the Phillips curve,

00:00:27.200 --> 00:00:32.870 align:middle line:84%
we talked about expectations
when we discussed the UIP and so

00:00:32.870 --> 00:00:35.840 align:middle line:84%
on, but expectation is a much
bigger issue in economics.

00:00:35.840 --> 00:00:37.940 align:middle line:84%
In fact, most
decisions by firms,

00:00:37.940 --> 00:00:41.810 align:middle line:84%
by consumers,
governments involve

00:00:41.810 --> 00:00:43.370 align:middle line:90%
considerations of the future.

00:00:43.370 --> 00:00:46.880 align:middle line:84%
And it plays an even bigger role
in finance in which essentially,

00:00:46.880 --> 00:00:48.440 align:middle line:90%
everything is about the future.

00:00:48.440 --> 00:00:52.400 align:middle line:84%
The price of an asset today
is meaningless in itself.

00:00:52.400 --> 00:00:54.650 align:middle line:84%
You have to compare it with
what you expect to get out

00:00:54.650 --> 00:00:55.860 align:middle line:90%
of that asset in the future.

00:00:55.860 --> 00:00:57.900 align:middle line:84%
So it's all about
expectations and so on.

00:00:57.900 --> 00:01:00.050 align:middle line:84%
So that's what we're
going to do today

00:01:00.050 --> 00:01:04.120 align:middle line:84%
we're going to talk
about expectations, how

00:01:04.120 --> 00:01:08.650 align:middle line:84%
to value things that you expect
to receive in the future,

00:01:08.650 --> 00:01:11.350 align:middle line:84%
and how to compare those
things with things that you

00:01:11.350 --> 00:01:14.570 align:middle line:90%
have in the present.

00:01:14.570 --> 00:01:17.420 align:middle line:84%
But before doing that, actually,
let's talk a little bit

00:01:17.420 --> 00:01:18.360 align:middle line:90%
about the news.

00:01:18.360 --> 00:01:21.950 align:middle line:84%
Who knows who first
Republic Bank is?

00:01:21.950 --> 00:01:24.230 align:middle line:84%
Remember that a few
weeks ago, I told you

00:01:24.230 --> 00:01:26.970 align:middle line:90%
that the Silicon Valley Bank--

00:01:26.970 --> 00:01:28.400 align:middle line:90%
I mean, you read it.

00:01:28.400 --> 00:01:33.120 align:middle line:90%
I just mentioned it, that the--

00:01:33.120 --> 00:01:37.730 align:middle line:84%
or discuss it that we had the
second-largest bank by asset

00:01:37.730 --> 00:01:40.070 align:middle line:90%
in US history--

00:01:40.070 --> 00:01:44.660 align:middle line:84%
it was-- Silicon Valley Bank
was the second-largest asset--

00:01:44.660 --> 00:01:47.840 align:middle line:84%
bank in terms of assets
to collapse in the US.

00:01:47.840 --> 00:01:50.360 align:middle line:84%
The first one was
many years ago,

00:01:50.360 --> 00:01:54.350 align:middle line:84%
and then we had this bank that
had more than $200 billion

00:01:54.350 --> 00:01:57.410 align:middle line:84%
in assets that essentially
collapsed in a few days.

00:01:57.410 --> 00:01:58.850 align:middle line:90%
It was a run on deposits.

00:01:58.850 --> 00:02:02.270 align:middle line:84%
They had problems
before, but what really

00:02:02.270 --> 00:02:04.430 align:middle line:84%
did it, as is always
the case with banks,

00:02:04.430 --> 00:02:08.090 align:middle line:84%
is they have a run on
deposits-- funding.

00:02:08.090 --> 00:02:09.690 align:middle line:90%
Well, it's no longer.

00:02:09.690 --> 00:02:13.160 align:middle line:84%
The second-largest collapse
in US bank history,

00:02:13.160 --> 00:02:17.780 align:middle line:84%
now we have on the weekend
the new second-largest bank

00:02:17.780 --> 00:02:20.930 align:middle line:84%
to collapse, which is First
Republic Bank that was

00:02:20.930 --> 00:02:25.790 align:middle line:84%
essentially liquidated and
sold to JPMorgan over--

00:02:25.790 --> 00:02:28.760 align:middle line:84%
today morning, very, very
early in the morning.

00:02:28.760 --> 00:02:31.640 align:middle line:84%
So you have an account
in First Republic Bank,

00:02:31.640 --> 00:02:34.490 align:middle line:84%
you soon are likely to have
an account in JPMorgan.

00:02:34.490 --> 00:02:37.760 align:middle line:84%
But again, what
made it collapse was

00:02:37.760 --> 00:02:40.820 align:middle line:84%
something very similar to
what made Silicon Valley Bank

00:02:40.820 --> 00:02:44.790 align:middle line:84%
collapse, which is that they had
invested on a series of things

00:02:44.790 --> 00:02:50.400 align:middle line:84%
that were very vulnerable to the
fast pace of hikes in interest

00:02:50.400 --> 00:02:51.660 align:middle line:90%
rates in the US.

00:02:51.660 --> 00:02:53.910 align:middle line:84%
And when they had those
losses, depositors

00:02:53.910 --> 00:02:56.610 align:middle line:84%
became worried about
it, and eventually they

00:02:56.610 --> 00:03:00.420 align:middle line:84%
decided not to wait, just
run and see what happened.

00:03:00.420 --> 00:03:03.030 align:middle line:84%
First Republic Bank
lost about $100 billion

00:03:03.030 --> 00:03:05.580 align:middle line:90%
in deposits just last week.

00:03:05.580 --> 00:03:07.170 align:middle line:90%
The last few days of last week.

00:03:07.170 --> 00:03:15.080 align:middle line:84%
So it was obvious that it
was not going to survive,

00:03:15.080 --> 00:03:18.490 align:middle line:84%
and that's the reason something
was arranged over the weekend

00:03:18.490 --> 00:03:21.650 align:middle line:84%
to avoid the panics associated
to collapse of the bank

00:03:21.650 --> 00:03:22.720 align:middle line:90%
and so on.

00:03:22.720 --> 00:03:25.690 align:middle line:84%
But anyways, by the way, this
is all about expectations,

00:03:25.690 --> 00:03:30.608 align:middle line:84%
is if people had expected the
deposits to remain in the bank,

00:03:30.608 --> 00:03:32.650 align:middle line:84%
then probably this bank
would not have collapsed.

00:03:32.650 --> 00:03:35.380 align:middle line:84%
It's all about people
anticipating what other people

00:03:35.380 --> 00:03:38.660 align:middle line:90%
will do and so on and so forth.

00:03:38.660 --> 00:03:43.170 align:middle line:84%
OK, but now let me get into
the specifics of this lecture.

00:03:43.170 --> 00:03:47.270 align:middle line:84%
So there, you have-- this is the
most important index of equity--

00:03:47.270 --> 00:03:49.700 align:middle line:90%
equity index in the US, S&P 500.

00:03:49.700 --> 00:03:53.390 align:middle line:84%
It's a very inclusive index
that captures all the large--

00:03:53.390 --> 00:03:56.150 align:middle line:84%
most of the large
companies in the US--

00:03:56.150 --> 00:03:57.770 align:middle line:90%
all of the large, I think--

00:03:57.770 --> 00:03:59.840 align:middle line:90%
companies in the US.

00:03:59.840 --> 00:04:02.660 align:middle line:84%
And that's an index, an
average-- weighted average

00:04:02.660 --> 00:04:07.790 align:middle line:84%
by this capitalization value
of each of these shares,

00:04:07.790 --> 00:04:10.670 align:middle line:84%
the weighted average of the
major-- main shares in the US,

00:04:10.670 --> 00:04:12.230 align:middle line:90%
equity shares in the US.

00:04:12.230 --> 00:04:15.470 align:middle line:84%
And one thing you see is
that it moves a lot around.

00:04:15.470 --> 00:04:19.250 align:middle line:84%
Here, for example,
when we became aware

00:04:19.250 --> 00:04:21.649 align:middle line:84%
that COVID was going
to be a serious issue,

00:04:21.649 --> 00:04:24.920 align:middle line:84%
the US equity market
collapsed by 35% or so.

00:04:24.920 --> 00:04:27.860 align:middle line:84%
That's a very large collapse
in a very short period of time.

00:04:27.860 --> 00:04:32.630 align:middle line:84%
And then, as a result of
lots of policy support,

00:04:32.630 --> 00:04:34.880 align:middle line:90%
actually we had a massive rally.

00:04:34.880 --> 00:04:37.670 align:middle line:84%
So up to the end of
2021, the equity market

00:04:37.670 --> 00:04:41.250 align:middle line:84%
had rallied by
114%, so big rally.

00:04:41.250 --> 00:04:44.010 align:middle line:84%
Then we got
inflation and the Fed

00:04:44.010 --> 00:04:47.910 align:middle line:84%
began to worry about inflation,
so they began to hike interest

00:04:47.910 --> 00:04:49.890 align:middle line:84%
rates, and when they
hike interest rates,

00:04:49.890 --> 00:04:52.680 align:middle line:84%
that eventually led to
a very large decline

00:04:52.680 --> 00:04:56.280 align:middle line:84%
in asset prices of the
order of 30% or so--

00:04:56.280 --> 00:05:00.300 align:middle line:84%
25% or so, actually, from
the peak to the bottom.

00:05:00.300 --> 00:05:03.550 align:middle line:84%
And then since the bottom,
which was more or less October

00:05:03.550 --> 00:05:07.500 align:middle line:84%
of last year, we have seen a
recovery of about 16% or so

00:05:07.500 --> 00:05:08.910 align:middle line:90%
of the equity market.

00:05:08.910 --> 00:05:11.970 align:middle line:84%
And if you look at the NASDAQ,
which is another one index that

00:05:11.970 --> 00:05:15.820 align:middle line:84%
is very loaded towards
technology companies,

00:05:15.820 --> 00:05:19.300 align:middle line:84%
and you can see swings
are even larger than that.

00:05:19.300 --> 00:05:22.650 align:middle line:84%
Now why do these
prices move so much?

00:05:22.650 --> 00:05:27.140 align:middle line:84%
Well, a lot of it has
to do with expectations.

00:05:27.140 --> 00:05:30.120 align:middle line:84%
Are things going to get
worse in the future?

00:05:30.120 --> 00:05:33.200 align:middle line:90%
Will the Fed cause a recession?

00:05:33.200 --> 00:05:35.570 align:middle line:84%
How much higher will
be the interest rates?

00:05:35.570 --> 00:05:38.750 align:middle line:84%
And things like that
matter a great deal.

00:05:38.750 --> 00:05:41.720 align:middle line:84%
Another thing that
matters a great deal

00:05:41.720 --> 00:05:45.543 align:middle line:84%
is how much people want to take
risk at any moment in time.

00:05:45.543 --> 00:05:47.210 align:middle line:84%
If you're very scared
about environment,

00:05:47.210 --> 00:05:49.520 align:middle line:84%
you're unlikely to want
to have something that--

00:05:49.520 --> 00:05:52.640 align:middle line:84%
to invest on something
that can move so much.

00:05:52.640 --> 00:05:56.120 align:middle line:84%
And so risk is well-known,
so it's called risk-off, when

00:05:56.120 --> 00:05:58.640 align:middle line:84%
people don't want to take
risk, these asset prices

00:05:58.640 --> 00:06:00.200 align:middle line:90%
tend to collapse.

00:06:00.200 --> 00:06:03.710 align:middle line:84%
Of Risky assets-- equity
is a very risky asset.

00:06:03.710 --> 00:06:06.320 align:middle line:84%
But that's not the only thing
that moves these assets around.

00:06:06.320 --> 00:06:08.990 align:middle line:84%
It's not just the risk that the
companies underlying companies

00:06:08.990 --> 00:06:11.270 align:middle line:84%
may go bankrupt or
anything like that.

00:06:11.270 --> 00:06:14.870 align:middle line:84%
Here, you have, for
example, the movement of a--

00:06:14.870 --> 00:06:16.640 align:middle line:84%
it's an ETF, but
it doesn't matter.

00:06:16.640 --> 00:06:18.710 align:middle line:90%
It's a portfolio of bonds--

00:06:18.710 --> 00:06:20.840 align:middle line:84%
of US Treasury bonds
of very long duration,

00:06:20.840 --> 00:06:24.170 align:middle line:84%
maturities beyond
20 years and so.

00:06:24.170 --> 00:06:27.890 align:middle line:84%
So this is incredibly safe bonds
because it's US treasuries.

00:06:27.890 --> 00:06:30.920 align:middle line:84%
So there's no risk of default
or anything like that.

00:06:30.920 --> 00:06:33.780 align:middle line:84%
Still, the price swings
can be pretty large.

00:06:33.780 --> 00:06:37.760 align:middle line:84%
I mean, over this period, you
have seen an increase in value

00:06:37.760 --> 00:06:44.240 align:middle line:84%
of 45%, then a decline
in value of about 20%,

00:06:44.240 --> 00:06:45.740 align:middle line:90%
another increase in 15%.

00:06:45.740 --> 00:06:51.410 align:middle line:84%
Here, there was a huge decline,
40% since essentially--

00:06:51.410 --> 00:06:52.820 align:middle line:90%
what do you think happened here?

00:06:52.820 --> 00:06:55.825 align:middle line:84%
Why is this big
decline in bonds?

00:06:55.825 --> 00:06:57.200 align:middle line:84%
You're going to
be able to answer

00:06:57.200 --> 00:06:59.990 align:middle line:84%
that very precisely later
on, but I can tell you

00:06:59.990 --> 00:07:03.170 align:middle line:84%
in advance, that was essentially
the result of monetary policy

00:07:03.170 --> 00:07:04.200 align:middle line:90%
tightening.

00:07:04.200 --> 00:07:09.030 align:middle line:84%
Increasing interest rates
caused the bonds to decline.

00:07:09.030 --> 00:07:11.300 align:middle line:84%
So even these instruments
are very safe in the sense

00:07:11.300 --> 00:07:13.190 align:middle line:84%
that if you hold
them to maturity,

00:07:13.190 --> 00:07:15.650 align:middle line:84%
you'll get your money back
and all the promised coupons

00:07:15.650 --> 00:07:19.070 align:middle line:84%
along the path, well still,
the price can move a lot.

00:07:19.070 --> 00:07:21.800 align:middle line:84%
And it's obvious that
that movement in price

00:07:21.800 --> 00:07:23.570 align:middle line:84%
is something that
you need to explain

00:07:23.570 --> 00:07:27.560 align:middle line:84%
in terms of expectations, what
people expect things to happen.

00:07:27.560 --> 00:07:30.020 align:middle line:84%
In this case, it's not whether
people expect to get paid

00:07:30.020 --> 00:07:33.140 align:middle line:84%
or not because you will get
paid, but it's expected--

00:07:33.140 --> 00:07:35.000 align:middle line:84%
but in this
particular case, it's

00:07:35.000 --> 00:07:37.293 align:middle line:84%
about expectations about
future interest rate.

00:07:37.293 --> 00:07:39.210 align:middle line:84%
You think the interest
rate will be very high,

00:07:39.210 --> 00:07:41.700 align:middle line:84%
then the price of bonds will
tend to be very low and so on,

00:07:41.700 --> 00:07:43.190 align:middle line:90%
but it's all about the future.

00:07:43.190 --> 00:07:45.740 align:middle line:90%


00:07:45.740 --> 00:07:50.420 align:middle line:84%
So a key concept that we're
going to discuss today,

00:07:50.420 --> 00:07:55.010 align:middle line:84%
and then you're going to use
it to price specific assets,

00:07:55.010 --> 00:07:58.340 align:middle line:84%
is a concept of expected
present discounted value,

00:07:58.340 --> 00:07:59.930 align:middle line:90%
and this is a loaded concept.

00:07:59.930 --> 00:08:02.060 align:middle line:84%
There's lots of
terms in there and we

00:08:02.060 --> 00:08:06.560 align:middle line:84%
need to understand what
each of these terms means.

00:08:06.560 --> 00:08:09.350 align:middle line:84%
So the key issue that
we're going to discuss

00:08:09.350 --> 00:08:10.805 align:middle line:90%
is how do we decide--

00:08:10.805 --> 00:08:12.680 align:middle line:84%
for example, if you see
the price of an asset

00:08:12.680 --> 00:08:15.560 align:middle line:84%
out there that is
100, how do you

00:08:15.560 --> 00:08:19.640 align:middle line:84%
decide whether that price is
fair or not, it looks cheap

00:08:19.640 --> 00:08:21.740 align:middle line:90%
or not?

00:08:21.740 --> 00:08:25.190 align:middle line:84%
And that question means
you have to decide

00:08:25.190 --> 00:08:27.440 align:middle line:84%
whether that price that
you're paying today

00:08:27.440 --> 00:08:29.930 align:middle line:84%
is consistent with
the future cash flows

00:08:29.930 --> 00:08:31.815 align:middle line:84%
that you're going to
get from these assets.

00:08:31.815 --> 00:08:33.440 align:middle line:84%
And that's the reason
you buy an asset,

00:08:33.440 --> 00:08:37.520 align:middle line:84%
is because you'll get something
in return in the future.

00:08:37.520 --> 00:08:38.780 align:middle line:90%
But how do we compare that?

00:08:38.780 --> 00:08:40.608 align:middle line:84%
How do we compare
the price today

00:08:40.608 --> 00:08:42.650 align:middle line:84%
with those things that
will happen in the future?

00:08:42.650 --> 00:08:46.700 align:middle line:90%


00:08:46.700 --> 00:08:48.820 align:middle line:84%
So answering that
question, which

00:08:48.820 --> 00:08:50.590 align:middle line:84%
is what we're going
to do in this lecture,

00:08:50.590 --> 00:08:53.710 align:middle line:90%
involves the following concepts.

00:08:53.710 --> 00:08:55.570 align:middle line:90%
First, expectations.

00:08:55.570 --> 00:08:57.380 align:middle line:90%
Big thing.

00:08:57.380 --> 00:08:58.280 align:middle line:90%
That's it.

00:08:58.280 --> 00:09:00.680 align:middle line:84%
This is expected present
discounted value.

00:09:00.680 --> 00:09:02.690 align:middle line:90%
The E part is for expectations.

00:09:02.690 --> 00:09:05.340 align:middle line:90%
That comes there.

00:09:05.340 --> 00:09:07.850 align:middle line:84%
The expectations are very
crucial because these are things

00:09:07.850 --> 00:09:09.140 align:middle line:90%
that happen in the future.

00:09:09.140 --> 00:09:10.280 align:middle line:90%
You need to expect--

00:09:10.280 --> 00:09:14.630 align:middle line:84%
even if it's a bond that
promises you to pay $0.50 per

00:09:14.630 --> 00:09:18.990 align:middle line:84%
dollar every six months, you
still may have an expectation

00:09:18.990 --> 00:09:21.600 align:middle line:84%
that if it is a bond issue
by First Republic Bank,

00:09:21.600 --> 00:09:22.620 align:middle line:90%
it may not pay.

00:09:22.620 --> 00:09:27.750 align:middle line:84%
So you need to have an
expectation about that.

00:09:27.750 --> 00:09:30.240 align:middle line:84%
So a crucial term
is expectation.

00:09:30.240 --> 00:09:33.720 align:middle line:84%
Then you need some
method to compare

00:09:33.720 --> 00:09:36.630 align:middle line:84%
payments received in the future
with payments made today.

00:09:36.630 --> 00:09:38.760 align:middle line:84%
I mean, if you buy an
asset you pay today,

00:09:38.760 --> 00:09:41.010 align:middle line:84%
but you're going to
receive things returns

00:09:41.010 --> 00:09:42.460 align:middle line:90%
for that asset in the future.

00:09:42.460 --> 00:09:44.970 align:middle line:90%
So how do you compare that?

00:09:44.970 --> 00:09:49.500 align:middle line:84%
Suppose I pay one today and I
receive one one year from now.

00:09:49.500 --> 00:09:52.610 align:middle line:84%
Does that seem
like a good asset?

00:09:52.610 --> 00:09:53.450 align:middle line:90%
Probably not.

00:09:53.450 --> 00:09:57.790 align:middle line:90%
I mean, probably not.

00:09:57.790 --> 00:10:01.030 align:middle line:84%
And that's what the word
"discounted" really means.

00:10:01.030 --> 00:10:04.330 align:middle line:84%
When you say expected
present discounted value,

00:10:04.330 --> 00:10:08.170 align:middle line:84%
it says, somehow that things
I receive in the future

00:10:08.170 --> 00:10:10.782 align:middle line:84%
are valued less than
things I have today.

00:10:10.782 --> 00:10:12.490 align:middle line:84%
So if you're going to
tell me that you're

00:10:12.490 --> 00:10:16.060 align:middle line:84%
going to pay me $1 in the future
and I have to pay you $1 today,

00:10:16.060 --> 00:10:18.670 align:middle line:84%
most likely I won't
take that deal.

00:10:18.670 --> 00:10:21.930 align:middle line:84%
So in other words, I'm
discounting the future.

00:10:21.930 --> 00:10:23.370 align:middle line:90%
How do we discount the future?

00:10:23.370 --> 00:10:27.110 align:middle line:84%
Well, something that we
now have to figure out.

00:10:27.110 --> 00:10:31.868 align:middle line:84%
So let me first shut down this
part, the expectations, and then

00:10:31.868 --> 00:10:32.660 align:middle line:90%
we'll introduce it.

00:10:32.660 --> 00:10:35.200 align:middle line:84%
So assume for now
that the future.

00:10:35.200 --> 00:10:38.395 align:middle line:84%
And I'm going to derive all
the equations with assuming

00:10:38.395 --> 00:10:39.650 align:middle line:90%
that you know the future.

00:10:39.650 --> 00:10:41.920 align:middle line:84%
So there's no issue of
trying to figure out what

00:10:41.920 --> 00:10:43.480 align:middle line:90%
the future is, you know it.

00:10:43.480 --> 00:10:46.720 align:middle line:84%
But still, you have
to decide whether--

00:10:46.720 --> 00:10:48.835 align:middle line:84%
what is the right
value for an asset.

00:10:48.835 --> 00:10:52.020 align:middle line:90%


00:10:52.020 --> 00:10:57.130 align:middle line:84%
OK, so let's start with the
case where you know the future.

00:10:57.130 --> 00:10:58.370 align:middle line:90%
Sorry.

00:10:58.370 --> 00:11:02.500 align:middle line:90%
And let's do the comparison--

00:11:02.500 --> 00:11:04.780 align:middle line:84%
let's try to understand
how do we move flows--

00:11:04.780 --> 00:11:07.480 align:middle line:84%
how do we value flows at
different points in time?

00:11:07.480 --> 00:11:09.550 align:middle line:84%
And the easiest
thing is think first

00:11:09.550 --> 00:11:11.740 align:middle line:84%
about comparing an
asset that gives you

00:11:11.740 --> 00:11:15.980 align:middle line:84%
$1 in the future, how much
do you think is worth today?

00:11:15.980 --> 00:11:18.850 align:middle line:84%
Well, the easiest way
to get to that value

00:11:18.850 --> 00:11:21.040 align:middle line:90%
is to think on the alternatives.

00:11:21.040 --> 00:11:26.180 align:middle line:84%
Suppose I have a dollar
today, what can I do with it?

00:11:26.180 --> 00:11:28.570 align:middle line:90%
Well-- in terms of investment?

00:11:28.570 --> 00:11:32.260 align:middle line:84%
Well, suppose that you have
available 1-year bonds,

00:11:32.260 --> 00:11:35.140 align:middle line:84%
Treasury bonds, and that
the interest rate is it.

00:11:35.140 --> 00:11:37.850 align:middle line:84%
That's the interest
rate on a 1-year bond.

00:11:37.850 --> 00:11:42.170 align:middle line:84%
So if you want-- if
you have a dollar,

00:11:42.170 --> 00:11:44.590 align:middle line:84%
you have the option to
invest it in that asset,

00:11:44.590 --> 00:11:51.530 align:middle line:84%
in that bond, which will give
you 1 plus i dollars next year.

00:11:51.530 --> 00:11:58.370 align:middle line:84%
Well, that means that I can
get $1 next year by investing

00:11:58.370 --> 00:12:02.260 align:middle line:90%
1 over 1 plus i dollars today.

00:12:02.260 --> 00:12:05.200 align:middle line:90%
Because if I invest 1 plus 1--

00:12:05.200 --> 00:12:08.830 align:middle line:84%
rather than $1, I invest
1 over 1 plus i today,

00:12:08.830 --> 00:12:11.500 align:middle line:84%
then I multiply
this by 1 plus i,

00:12:11.500 --> 00:12:14.120 align:middle line:84%
and I get my dollar
in the future.

00:12:14.120 --> 00:12:16.210 align:middle line:84%
So that tells me
that-- say the interest

00:12:16.210 --> 00:12:22.430 align:middle line:84%
rate is 10%, then with $1 today,
I can get $1.1 in the future.

00:12:22.430 --> 00:12:27.100 align:middle line:84%
That means that investing
$0.90 today, more or less,

00:12:27.100 --> 00:12:29.320 align:middle line:84%
I can get a bucket
in the future.

00:12:29.320 --> 00:12:33.760 align:middle line:84%
That tells me that $1 in the
future is equivalent to $0.90

00:12:33.760 --> 00:12:36.790 align:middle line:90%
today with that assumption.

00:12:36.790 --> 00:12:39.700 align:middle line:84%
So that's the reason when I
told you the deal of, look,

00:12:39.700 --> 00:12:42.220 align:middle line:84%
I have an asset
that costs you $1,

00:12:42.220 --> 00:12:44.110 align:middle line:84%
but it gives you
$1 in the future,

00:12:44.110 --> 00:12:47.480 align:middle line:84%
and that's not a good deal if
the interest rate is positive.

00:12:47.480 --> 00:12:51.530 align:middle line:84%
If the interest rate is 10%,
then a fair comparison is $0.90

00:12:51.530 --> 00:12:54.590 align:middle line:90%
with $1, not $1 with $1.

00:12:54.590 --> 00:12:57.290 align:middle line:84%
So that's a discounting
of the future.

00:12:57.290 --> 00:12:59.810 align:middle line:84%
The most obvious way of
discounting the future

00:12:59.810 --> 00:13:04.150 align:middle line:84%
is to discount it by
the interest rate.

00:13:04.150 --> 00:13:05.830 align:middle line:90%
Which interest rate to pick?

00:13:05.830 --> 00:13:06.820 align:middle line:90%
That's more subtle.

00:13:06.820 --> 00:13:09.190 align:middle line:84%
That depends on risk, it
depends on many other things,

00:13:09.190 --> 00:13:12.320 align:middle line:84%
which we're going to
discuss to some extent here.

00:13:12.320 --> 00:13:14.837 align:middle line:84%
But for now, let's
make it very simple.

00:13:14.837 --> 00:13:17.170 align:middle line:84%
And in a world which you
really know the future, really,

00:13:17.170 --> 00:13:19.330 align:middle line:84%
the right interest to use
is the safe interest--

00:13:19.330 --> 00:13:23.680 align:middle line:84%
the interest rate of Treasury
bonds and things like that.

00:13:23.680 --> 00:13:25.540 align:middle line:90%
So that's that.

00:13:25.540 --> 00:13:27.640 align:middle line:84%
What about the dollar
that you receive--

00:13:27.640 --> 00:13:29.500 align:middle line:84%
what about if you are
thinking about what

00:13:29.500 --> 00:13:31.660 align:middle line:84%
is the value of $1
two years from now?

00:13:31.660 --> 00:13:34.210 align:middle line:90%


00:13:34.210 --> 00:13:36.460 align:middle line:84%
Well, if I get a $1,
can do the same logic.

00:13:36.460 --> 00:13:39.160 align:middle line:90%
If I can use the same logic.

00:13:39.160 --> 00:13:43.390 align:middle line:84%
If I get a $1 today, I
can convert that into 1

00:13:43.390 --> 00:13:48.490 align:middle line:90%
plus it times 1 plus it plus $1.

00:13:48.490 --> 00:13:52.360 align:middle line:84%
So say 10% and 10%,
I get 1.1 next year,

00:13:52.360 --> 00:13:56.740 align:middle line:84%
and then I get 1.1 times 1.1,
1.21 or something like that.

00:13:56.740 --> 00:14:01.380 align:middle line:90%
That's my final result.

00:14:01.380 --> 00:14:04.770 align:middle line:84%
Well, then, how much is
it worth to have $1--

00:14:04.770 --> 00:14:09.110 align:middle line:84%
$1 asset that gives you
$1 two years from now?

00:14:09.110 --> 00:14:11.800 align:middle line:84%
Well, it's going
to be $1 divided

00:14:11.800 --> 00:14:15.060 align:middle line:84%
by the product of
this interest rate.

00:14:15.060 --> 00:14:15.930 align:middle line:90%
Why is that?

00:14:15.930 --> 00:14:20.166 align:middle line:84%
Well, because with this
amount of dollars today--

00:14:20.166 --> 00:14:22.950 align:middle line:84%
at this point, $0.80,
something like that,

00:14:22.950 --> 00:14:25.980 align:middle line:84%
I can generate $1
two years from now.

00:14:25.980 --> 00:14:35.820 align:middle line:84%
That means $1 two years from
now is worth about $0.80 today.

00:14:35.820 --> 00:14:38.790 align:middle line:84%
We're going to use a
lot this type of logic.

00:14:38.790 --> 00:14:42.180 align:middle line:84%
And I know that it may not be
that intuitive the first time

00:14:42.180 --> 00:14:44.280 align:middle line:90%
you see it, but ask questions.

00:14:44.280 --> 00:14:47.860 align:middle line:90%


00:14:47.860 --> 00:14:49.030 align:middle line:90%
You want me to repeat it?

00:14:49.030 --> 00:14:54.460 align:middle line:90%


00:14:54.460 --> 00:14:55.390 align:middle line:90%
OK.

00:14:55.390 --> 00:14:57.410 align:middle line:90%
The final goal is the following.

00:14:57.410 --> 00:14:59.890 align:middle line:84%
We're going to-- what comes
next, we're going to see,

00:14:59.890 --> 00:15:02.630 align:middle line:84%
which happens again with
many decisions in life,

00:15:02.630 --> 00:15:05.050 align:middle line:84%
but particularly for
financial assets,

00:15:05.050 --> 00:15:08.700 align:middle line:84%
we're going to try to
value something that--

00:15:08.700 --> 00:15:12.190 align:middle line:84%
it was payoff happens at
different times in the future.

00:15:12.190 --> 00:15:14.500 align:middle line:84%
And the question
is, how do I value

00:15:14.500 --> 00:15:18.730 align:middle line:84%
an asset that pays me
$5 one year from now,

00:15:18.730 --> 00:15:24.940 align:middle line:84%
$25 three years from now,
minus $10 10 years from now,

00:15:24.940 --> 00:15:27.280 align:middle line:90%
plus $50 $100 from now?

00:15:27.280 --> 00:15:28.735 align:middle line:90%
What is the value of that?

00:15:28.735 --> 00:15:31.100 align:middle line:90%
Of having an asset like that?

00:15:31.100 --> 00:15:35.410 align:middle line:84%
And so I need some method
to bring it to today's value

00:15:35.410 --> 00:15:38.320 align:middle line:84%
because today, I have a
meaning of what $1 is,

00:15:38.320 --> 00:15:42.670 align:middle line:84%
and therefore, I can compare
it with whatever price.

00:15:42.670 --> 00:15:44.900 align:middle line:84%
People are asking
me for that asset.

00:15:44.900 --> 00:15:48.430 align:middle line:84%
So what this is doing
is it's doing that.

00:15:48.430 --> 00:15:51.760 align:middle line:84%
It's telling you how to
convert $1 at different parts

00:15:51.760 --> 00:15:54.550 align:middle line:90%
in the future into $1 today.

00:15:54.550 --> 00:15:59.650 align:middle line:84%
And by that logic, the recipe
is, well, use the interest rate

00:15:59.650 --> 00:16:01.880 align:middle line:84%
because you could always
go the other way around.

00:16:01.880 --> 00:16:04.270 align:middle line:84%
You could always-- you can
ask a question, with $1

00:16:04.270 --> 00:16:08.010 align:middle line:84%
today, how many dollars can I
get two years from now, say,

00:16:08.010 --> 00:16:08.820 align:middle line:90%
that?

00:16:08.820 --> 00:16:11.010 align:middle line:90%
Well, say x?

00:16:11.010 --> 00:16:15.180 align:middle line:84%
Well, then I need 1 over
x, then $1 there is worth 1

00:16:15.180 --> 00:16:16.950 align:middle line:90%
over x dollars today.

00:16:16.950 --> 00:16:18.030 align:middle line:90%
That's the logic.

00:16:18.030 --> 00:16:21.120 align:middle line:90%
Because 1 over x times x is 1.

00:16:21.120 --> 00:16:25.527 align:middle line:90%
So let's do first problem here.

00:16:25.527 --> 00:16:30.300 align:middle line:90%


00:16:30.300 --> 00:16:32.215 align:middle line:90%
With $1 today-- oops.

00:16:32.215 --> 00:16:35.550 align:middle line:90%


00:16:35.550 --> 00:16:46.740 align:middle line:84%
I can generally say
$1.1 at t equal 2.

00:16:46.740 --> 00:16:51.030 align:middle line:84%
Then the question I want to
know is, how much is $1 worth--

00:16:51.030 --> 00:16:56.800 align:middle line:84%
how much is $1 received at
time t equal 2 worth today?

00:16:56.800 --> 00:16:58.660 align:middle line:84%
That's the question
I'm trying to answer.

00:16:58.660 --> 00:17:00.730 align:middle line:84%
Because an asset
will be something

00:17:00.730 --> 00:17:02.120 align:middle line:90%
that will pay you in the future.

00:17:02.120 --> 00:17:06.430 align:middle line:84%
So I want to know, how much is
$1 received in the future worth

00:17:06.430 --> 00:17:08.200 align:middle line:90%
today?

00:17:08.200 --> 00:17:12.460 align:middle line:84%
And then the answer
is, well, then it's--

00:17:12.460 --> 00:17:14.470 align:middle line:84%
I know the answer
from this logic

00:17:14.470 --> 00:17:21.440 align:middle line:84%
because I know that with 1,
if I have 1 over $1.1 today,

00:17:21.440 --> 00:17:27.079 align:middle line:90%
I can convert it into 1.

00:17:27.079 --> 00:17:28.369 align:middle line:90%
How do I know that?

00:17:28.369 --> 00:17:44.130 align:middle line:84%
Because 1 over 1.1
times 1.1 is equal to 1.

00:17:44.130 --> 00:17:47.840 align:middle line:84%
If I invest this
dollars today, I'm

00:17:47.840 --> 00:17:49.940 align:middle line:84%
going to get this
return on that.

00:17:49.940 --> 00:17:52.280 align:middle line:84%
And the product of this
thing gives me my dollar.

00:17:52.280 --> 00:17:54.830 align:middle line:90%


00:17:54.830 --> 00:17:58.040 align:middle line:84%
So if I tell you, do you prefer
to have $1 two days from-- two

00:17:58.040 --> 00:18:02.090 align:middle line:84%
years from now or today, you
say, I prefer it-- obviously

00:18:02.090 --> 00:18:07.630 align:middle line:84%
I prefer it today because I can
get $1.1 two years from now.

00:18:07.630 --> 00:18:09.940 align:middle line:84%
But then the more relevant
question is, no, no,

00:18:09.940 --> 00:18:13.660 align:middle line:84%
but then do you prefer to
have $0.90 today versus $1

00:18:13.660 --> 00:18:14.890 align:middle line:90%
in the future?

00:18:14.890 --> 00:18:17.500 align:middle line:84%
Then I need to do my
multiplication because then I

00:18:17.500 --> 00:18:21.220 align:middle line:84%
have to multiply the $0.90 by
the 1.1 and see whether I get

00:18:21.220 --> 00:18:23.950 align:middle line:84%
something comparable
to $1 or not.

00:18:23.950 --> 00:18:27.970 align:middle line:84%
But that's the
logic behind that.

00:18:27.970 --> 00:18:32.980 align:middle line:84%
So the interest rate is what
we discount the future by.

00:18:32.980 --> 00:18:35.530 align:middle line:84%
And it's natural because if the
interest rate is very high--

00:18:35.530 --> 00:18:38.300 align:middle line:84%
if the interest
rate is 0, say, then

00:18:38.300 --> 00:18:40.840 align:middle line:84%
$1 received two years from
now and $1 received today

00:18:40.840 --> 00:18:43.927 align:middle line:84%
is the same because I
can-- if I invest $1 today

00:18:43.927 --> 00:18:45.760 align:middle line:84%
and the interest rate
is 0, I'm going to get

00:18:45.760 --> 00:18:47.780 align:middle line:90%
my $1 two years from now.

00:18:47.780 --> 00:18:50.843 align:middle line:84%
If the interest rate is 50%,
it makes a big difference

00:18:50.843 --> 00:18:52.760 align:middle line:84%
receiving the dollar
today versus receiving it

00:18:52.760 --> 00:18:54.110 align:middle line:90%
two years from now.

00:18:54.110 --> 00:18:56.540 align:middle line:84%
If you're in Argentina
and the interest rate--

00:18:56.540 --> 00:18:59.060 align:middle line:84%
I don't know what
it is, it's 700%.

00:18:59.060 --> 00:19:02.720 align:middle line:84%
It makes a huge difference
whether you receive it one year

00:19:02.720 --> 00:19:05.710 align:middle line:90%
from now than today.

00:19:05.710 --> 00:19:09.920 align:middle line:84%
And so that's the role
of the interest rate.

00:19:09.920 --> 00:19:13.160 align:middle line:84%
The higher the
interest rate, the less

00:19:13.160 --> 00:19:15.620 align:middle line:84%
is $1 received in
the future worth

00:19:15.620 --> 00:19:18.110 align:middle line:84%
relative to $1 received
today because you

00:19:18.110 --> 00:19:21.080 align:middle line:84%
can get a much higher return
from the dollar you have today

00:19:21.080 --> 00:19:22.460 align:middle line:90%
if the interest rate is high.

00:19:22.460 --> 00:19:26.143 align:middle line:84%
The interest rate is low,
you don't get that much.

00:19:26.143 --> 00:19:26.810 align:middle line:90%
Much difference.

00:19:26.810 --> 00:19:28.160 align:middle line:90%
OK, good.

00:19:28.160 --> 00:19:29.750 align:middle line:90%
So this is a big principle.

00:19:29.750 --> 00:19:32.330 align:middle line:84%
And, I mean,
everything that I'll

00:19:32.330 --> 00:19:34.070 align:middle line:90%
say next builds on this logic.

00:19:34.070 --> 00:19:38.590 align:middle line:90%


00:19:38.590 --> 00:19:41.110 align:middle line:84%
So let me give you
a general formula.

00:19:41.110 --> 00:19:45.060 align:middle line:84%
So let's ask, what is the
value of an asset that

00:19:45.060 --> 00:19:51.990 align:middle line:84%
gives payouts of zt
dollars this year,

00:19:51.990 --> 00:19:55.830 align:middle line:84%
zt plus 1 one year from
now, zt plus 2 two years

00:19:55.830 --> 00:20:01.890 align:middle line:84%
from now, and so on and so
forth for n periods more?

00:20:01.890 --> 00:20:05.790 align:middle line:84%
Well, I just need to do
several of these operations.

00:20:05.790 --> 00:20:09.390 align:middle line:84%
I know that $1 received
this year is worth $1.

00:20:09.390 --> 00:20:10.800 align:middle line:90%
That's zt.

00:20:10.800 --> 00:20:16.500 align:middle line:84%
$1 received one year from
now is not the same as $1

00:20:16.500 --> 00:20:17.160 align:middle line:90%
received today.

00:20:17.160 --> 00:20:21.910 align:middle line:84%
It's the same as 1 over 1
plus it dollar received today.

00:20:21.910 --> 00:20:24.600 align:middle line:84%
So that cash flow I'm going
to receive from this asset

00:20:24.600 --> 00:20:26.250 align:middle line:90%
is worth this amount.

00:20:26.250 --> 00:20:29.280 align:middle line:84%
For something that I
received two years from now,

00:20:29.280 --> 00:20:32.640 align:middle line:84%
then it's not--
certainly it's much less

00:20:32.640 --> 00:20:34.050 align:middle line:90%
than receiving $1 today.

00:20:34.050 --> 00:20:38.910 align:middle line:84%
It's going to be 1 over 1
plus it 1 plus it plus 1.

00:20:38.910 --> 00:20:41.370 align:middle line:84%
And that I have to multiply
by the number of dollars

00:20:41.370 --> 00:20:43.830 align:middle line:84%
I will receive two
years from now.

00:20:43.830 --> 00:20:46.550 align:middle line:90%
And I keep going.

00:20:46.550 --> 00:20:50.230 align:middle line:90%
So that's the present value.

00:20:50.230 --> 00:20:52.450 align:middle line:84%
Present discounted
value-- present

00:20:52.450 --> 00:20:54.490 align:middle line:84%
because I'm bringing
all these future cash

00:20:54.490 --> 00:20:56.450 align:middle line:90%
flows to the present.

00:20:56.450 --> 00:20:58.330 align:middle line:84%
That's what each of
these terms is doing.

00:20:58.330 --> 00:21:01.450 align:middle line:84%
The 1 over that is
bringing it to the present.

00:21:01.450 --> 00:21:04.760 align:middle line:84%
Discounted because the interest
rate is discounting things,

00:21:04.760 --> 00:21:06.190 align:middle line:90%
making them smaller.

00:21:06.190 --> 00:21:08.890 align:middle line:84%
And value because I'm
trying to reduce them

00:21:08.890 --> 00:21:12.570 align:middle line:90%
to the current value.

00:21:12.570 --> 00:21:14.550 align:middle line:84%
That's a general formula,
so it's a formula

00:21:14.550 --> 00:21:15.690 align:middle line:90%
you need to understand.

00:21:15.690 --> 00:21:19.140 align:middle line:84%
It's just-- so that was
an asset that gives you

00:21:19.140 --> 00:21:23.800 align:middle line:84%
z dollars today, zt plus
1 one year from now,

00:21:23.800 --> 00:21:25.050 align:middle line:90%
so you use this formula.

00:21:25.050 --> 00:21:28.830 align:middle line:84%
Zt plus 2 two years from
now, so you use this formula,

00:21:28.830 --> 00:21:29.850 align:middle line:90%
and then you keep going.

00:21:29.850 --> 00:21:33.190 align:middle line:90%


00:21:33.190 --> 00:21:35.950 align:middle line:84%
What if we don't
know the future?

00:21:35.950 --> 00:21:38.990 align:middle line:84%
I had to remove
the expected part.

00:21:38.990 --> 00:21:42.020 align:middle line:84%
Well, if we don't know
the future, then the best

00:21:42.020 --> 00:21:42.862 align:middle line:90%
we can do--

00:21:42.862 --> 00:21:44.570 align:middle line:84%
in fact, we do fancier
things, but that's

00:21:44.570 --> 00:21:47.970 align:middle line:84%
what we want-- all that
we'll do in this course.

00:21:47.970 --> 00:21:50.030 align:middle line:84%
All that you can
do is just replace

00:21:50.030 --> 00:21:54.980 align:middle line:84%
the known quantities we have
here for the expectations.

00:21:54.980 --> 00:21:56.090 align:middle line:90%
So that's the closest.

00:21:56.090 --> 00:21:59.870 align:middle line:84%
So I know zt, that's
the cash flow I get now,

00:21:59.870 --> 00:22:04.040 align:middle line:84%
but I don't know zt plus 1, so
I can replace it by expectation.

00:22:04.040 --> 00:22:08.000 align:middle line:84%
I do know the interest rate on
a 1-year bond from today to one

00:22:08.000 --> 00:22:10.610 align:middle line:84%
year, so that's the reason I
don't need an expectation here.

00:22:10.610 --> 00:22:14.430 align:middle line:84%
But I don't know what the 1-year
rate will be one year from now,

00:22:14.430 --> 00:22:17.204 align:middle line:84%
so that's the reason I
need an expectation there.

00:22:17.204 --> 00:22:18.485 align:middle line:90%
And so on.

00:22:18.485 --> 00:22:21.110 align:middle line:84%
And I don't know what the cash
flow will be two years from now.

00:22:21.110 --> 00:22:23.402 align:middle line:84%
I have an expectation about
what the cash flow will be,

00:22:23.402 --> 00:22:26.750 align:middle line:84%
but I don't know it, so I
have an expectation there.

00:22:26.750 --> 00:22:30.920 align:middle line:84%
So all that I've
done here is say, OK,

00:22:30.920 --> 00:22:33.493 align:middle line:84%
acknowledge that this guy
knew a little bit too much.

00:22:33.493 --> 00:22:35.660 align:middle line:84%
He knew exactly what the
cash flows were going to be

00:22:35.660 --> 00:22:38.660 align:middle line:84%
in the future, and he knew what
the 1-year rates were going

00:22:38.660 --> 00:22:40.480 align:middle line:90%
to be in the future.

00:22:40.480 --> 00:22:42.010 align:middle line:90%
This guy here knows less.

00:22:42.010 --> 00:22:45.070 align:middle line:84%
He knows the cash flow today, he
knows the interest rate today,

00:22:45.070 --> 00:22:48.100 align:middle line:84%
but he doesn't know the cash
flows-- really has a hunch,

00:22:48.100 --> 00:22:51.137 align:middle line:84%
but he doesn't know the cash
flows one year, two years,

00:22:51.137 --> 00:22:52.720 align:middle line:84%
three years, and so
on for the future,

00:22:52.720 --> 00:22:56.530 align:middle line:84%
and it doesn't know the 1-year
interest rate in the future.

00:22:56.530 --> 00:22:58.930 align:middle line:84%
So all these expectations,
here is important

00:22:58.930 --> 00:22:59.790 align:middle line:90%
the concept of time.

00:22:59.790 --> 00:23:02.010 align:middle line:84%
These are expectations
as of time t.

00:23:02.010 --> 00:23:03.750 align:middle line:84%
At time t, you have
some information

00:23:03.750 --> 00:23:06.790 align:middle line:84%
and you make forecasts
about the future.

00:23:06.790 --> 00:23:07.980 align:middle line:90%
Use whatever you want.

00:23:07.980 --> 00:23:09.190 align:middle line:90%
Machine learning, whatever.

00:23:09.190 --> 00:23:11.190 align:middle line:84%
But you have
information at time t,

00:23:11.190 --> 00:23:14.640 align:middle line:84%
and then you have a forecast
for the future at t plus 1.

00:23:14.640 --> 00:23:17.050 align:middle line:84%
You have more information,
so you make another forecast,

00:23:17.050 --> 00:23:18.100 align:middle line:90%
and so on and so forth.

00:23:18.100 --> 00:23:21.270 align:middle line:84%
But in this-- we're
valuing an asset at time t,

00:23:21.270 --> 00:23:25.440 align:middle line:84%
then all these expectations
are taken as of time t.

00:23:25.440 --> 00:23:29.803 align:middle line:84%
That means given the information
you have available at time t.

00:23:29.803 --> 00:23:31.220 align:middle line:84%
That's the reason
these guys don't

00:23:31.220 --> 00:23:32.690 align:middle line:84%
have expectations
in front of them

00:23:32.690 --> 00:23:36.630 align:middle line:90%
because you know this at time t.

00:23:36.630 --> 00:23:38.730 align:middle line:84%
How do we take in the
value at t minus 1,

00:23:38.730 --> 00:23:41.610 align:middle line:84%
we would have not known that
and we had to-- an expectation

00:23:41.610 --> 00:23:46.740 align:middle line:84%
because there would have been
expectation of t minus 1.

00:23:46.740 --> 00:23:48.850 align:middle line:84%
OK, so that's your
big formula there.

00:23:48.850 --> 00:23:55.530 align:middle line:84%
So there are some examples
that are well-known,

00:23:55.530 --> 00:23:58.080 align:middle line:90%
and so let me show you.

00:23:58.080 --> 00:24:00.330 align:middle line:90%
They have nicer expressions.

00:24:00.330 --> 00:24:05.890 align:middle line:84%
So that's an example of
valuation of the same asset,

00:24:05.890 --> 00:24:08.990 align:middle line:84%
but when the interest
rate is constant.

00:24:08.990 --> 00:24:11.360 align:middle line:84%
Then obviously I don't
need all these products

00:24:11.360 --> 00:24:12.450 align:middle line:90%
in the denominator.

00:24:12.450 --> 00:24:16.070 align:middle line:84%
I have a constant
interest rate, then

00:24:16.070 --> 00:24:18.540 align:middle line:84%
I just get powers of
that interest rate.

00:24:18.540 --> 00:24:21.000 align:middle line:84%
That's one in which you
have constant payments.

00:24:21.000 --> 00:24:23.740 align:middle line:84%
So the interest rate
may be different,

00:24:23.740 --> 00:24:27.390 align:middle line:84%
but the payments are
the same over time.

00:24:27.390 --> 00:24:29.180 align:middle line:90%
So that's that.

00:24:29.180 --> 00:24:31.570 align:middle line:90%
So those are two easy formulas.

00:24:31.570 --> 00:24:35.110 align:middle line:84%
That's one in which you have
both constants, the interest

00:24:35.110 --> 00:24:39.220 align:middle line:84%
rate and the payment, then
you get a nice expression

00:24:39.220 --> 00:24:42.070 align:middle line:90%
that's just that.

00:24:42.070 --> 00:24:49.580 align:middle line:84%
You recognize that-- if you have
a constant interest rate here,

00:24:49.580 --> 00:24:53.640 align:middle line:84%
you see that the
value is declining--

00:24:53.640 --> 00:24:55.670 align:middle line:90%
is a geometric series.

00:24:55.670 --> 00:24:59.420 align:middle line:84%
The value of two years from
now is a square of 1 over 1

00:24:59.420 --> 00:25:00.560 align:middle line:90%
plus some--

00:25:00.560 --> 00:25:04.100 align:middle line:84%
is a square of a
number less than 1.

00:25:04.100 --> 00:25:06.680 align:middle line:84%
1 over 1 plus i is some
number less than 1.

00:25:06.680 --> 00:25:09.150 align:middle line:84%
This is the square of that,
then the cube, and so on.

00:25:09.150 --> 00:25:11.660 align:middle line:84%
So it's a geometric series
that is declining in the rate 1

00:25:11.660 --> 00:25:12.250 align:middle line:90%
plus i--

00:25:12.250 --> 00:25:13.760 align:middle line:90%
1 over 1 plus i.

00:25:13.760 --> 00:25:15.800 align:middle line:84%
Or declining at
the rate 1 plus i.

00:25:15.800 --> 00:25:19.520 align:middle line:90%
So that's your geometric series.

00:25:19.520 --> 00:25:22.860 align:middle line:90%
That's the value of that.

00:25:22.860 --> 00:25:25.950 align:middle line:84%
Constant rate and
payment forever.

00:25:25.950 --> 00:25:30.958 align:middle line:84%
Suppose you have an
asset that lives forever.

00:25:30.958 --> 00:25:32.250 align:middle line:90%
There are some bonds like that.

00:25:32.250 --> 00:25:33.720 align:middle line:90%
It's called perpetuities.

00:25:33.720 --> 00:25:36.580 align:middle line:90%


00:25:36.580 --> 00:25:38.530 align:middle line:90%
The US has an issue--

00:25:38.530 --> 00:25:40.730 align:middle line:90%
the UK has and so on.

00:25:40.730 --> 00:25:42.850 align:middle line:84%
So that's an asset, for
example, that pays you

00:25:42.850 --> 00:25:45.790 align:middle line:90%
a fixed amount forever.

00:25:45.790 --> 00:25:47.650 align:middle line:84%
And it's the interest
rate is constant,

00:25:47.650 --> 00:25:50.560 align:middle line:84%
that's a trickier thing, then
the value of that asset you

00:25:50.560 --> 00:25:55.260 align:middle line:84%
can see, that this is going to
0, so the value of that asset

00:25:55.260 --> 00:25:56.880 align:middle line:90%
is that.

00:25:56.880 --> 00:25:58.650 align:middle line:84%
And actually, a
formula that you may

00:25:58.650 --> 00:26:03.870 align:middle line:84%
see that is very often used as a
first approximation is this one.

00:26:03.870 --> 00:26:09.300 align:middle line:84%
This is the same asset, but it's
called x dividend or x coupon.

00:26:09.300 --> 00:26:13.920 align:middle line:84%
It's after the coupon of
this year has been paid.

00:26:13.920 --> 00:26:16.530 align:middle line:84%
So it's an asset that
starts paying at t plus 1,

00:26:16.530 --> 00:26:19.060 align:middle line:90%
is zt plus 1, plus 2, and so on.

00:26:19.060 --> 00:26:22.770 align:middle line:84%
Well, that is the same as
this minus the first coupon,

00:26:22.770 --> 00:26:24.510 align:middle line:90%
so it's equal to that.

00:26:24.510 --> 00:26:29.210 align:middle line:90%


00:26:29.210 --> 00:26:30.585 align:middle line:84%
That's an interesting
thing, huh?

00:26:30.585 --> 00:26:32.040 align:middle line:84%
Look, what happened
to this asset

00:26:32.040 --> 00:26:33.332 align:middle line:90%
as the interest rate goes to 0?

00:26:33.332 --> 00:26:35.920 align:middle line:90%


00:26:35.920 --> 00:26:39.670 align:middle line:84%
So this is an asset that
lasts for a very long time.

00:26:39.670 --> 00:26:43.540 align:middle line:84%
And look, we got to
a valuation formula.

00:26:43.540 --> 00:26:45.370 align:middle line:84%
What is happening
as the interest

00:26:45.370 --> 00:26:47.745 align:middle line:90%
rate goes to 0 to the line?

00:26:47.745 --> 00:26:49.370 align:middle line:84%
AUDIENCE: The value
becomes very large.

00:26:49.370 --> 00:26:49.780 align:middle line:90%
RICARDO CABALLERO: Very large.

00:26:49.780 --> 00:26:51.130 align:middle line:90%
It goes to infinity.

00:26:51.130 --> 00:26:55.060 align:middle line:84%
And a lot of what has happened
in global financial markets

00:26:55.060 --> 00:26:58.540 align:middle line:84%
in the last few years
has to do with that.

00:26:58.540 --> 00:27:01.190 align:middle line:84%
Interest rates were
very, very, very low.

00:27:01.190 --> 00:27:03.730 align:middle line:84%
And so most assets
that had long-duration

00:27:03.730 --> 00:27:04.715 align:middle line:90%
had very high values.

00:27:04.715 --> 00:27:07.273 align:middle line:90%


00:27:07.273 --> 00:27:08.690 align:middle line:84%
And it has a lot
to do with that--

00:27:08.690 --> 00:27:11.070 align:middle line:84%
monetary policy
has a lot to do--

00:27:11.070 --> 00:27:13.550 align:middle line:84%
whether it was a right
monetary policy or not,

00:27:13.550 --> 00:27:15.110 align:middle line:84%
that's something
to be discussed.

00:27:15.110 --> 00:27:17.360 align:middle line:84%
I think, on average, it was
the right monetary policy,

00:27:17.360 --> 00:27:19.110 align:middle line:84%
but one of the things
it did, it increased

00:27:19.110 --> 00:27:20.810 align:middle line:90%
the value of many assets.

00:27:20.810 --> 00:27:22.640 align:middle line:84%
In fact, that's one
of the mechanisms

00:27:22.640 --> 00:27:24.828 align:middle line:84%
through which monetary
policy works in practice.

00:27:24.828 --> 00:27:26.370 align:middle line:84%
It's not something
we have discussed,

00:27:26.370 --> 00:27:28.850 align:middle line:84%
but you can begin to see
here because if the value

00:27:28.850 --> 00:27:31.160 align:middle line:84%
of all assets go up a
lot, people feel wealthier

00:27:31.160 --> 00:27:33.398 align:middle line:84%
and that will tend to
consume more, and so on.

00:27:33.398 --> 00:27:35.690 align:middle line:84%
Well, this is one of the
channels monetary policy does.

00:27:35.690 --> 00:27:37.790 align:middle line:84%
By the way this
effect happens also

00:27:37.790 --> 00:27:39.540 align:middle line:84%
to the assets that
are finite end.

00:27:39.540 --> 00:27:41.030 align:middle line:90%
It's just that this goes--

00:27:41.030 --> 00:27:44.750 align:middle line:84%
it's maximized when this
asset lasts forever.

00:27:44.750 --> 00:27:47.760 align:middle line:84%
This asset literally
goes to infinity

00:27:47.760 --> 00:27:51.880 align:middle line:90%
if the interest rate goes to 0.

00:27:51.880 --> 00:27:54.700 align:middle line:84%
Well, if an acid
lasts for 10 periods,

00:27:54.700 --> 00:27:58.980 align:middle line:84%
it doesn't go to infinity,
it goes to n times z.

00:27:58.980 --> 00:27:59.480 align:middle line:90%
For some.

00:27:59.480 --> 00:28:02.775 align:middle line:84%
If the interest rate
is 0, just some things.

00:28:02.775 --> 00:28:04.610 align:middle line:90%
You see that?

00:28:04.610 --> 00:28:08.540 align:middle line:84%
If an asset lasts for n
periods, and it gives me

00:28:08.540 --> 00:28:11.790 align:middle line:84%
a payment of z in
every single period,

00:28:11.790 --> 00:28:13.470 align:middle line:84%
then when the interest
is 0, that asset

00:28:13.470 --> 00:28:18.320 align:middle line:84%
is worth n times z because
I will receive z coupons.

00:28:18.320 --> 00:28:21.610 align:middle line:84%
And don't discount the future
because the interest rate is 0.

00:28:21.610 --> 00:28:23.890 align:middle line:84%
What happens is, when
the asset lasts forever,

00:28:23.890 --> 00:28:26.830 align:middle line:84%
then n times z is a
very large number.

00:28:26.830 --> 00:28:31.920 align:middle line:84%
And that's what this
expression captures here.

00:28:31.920 --> 00:28:34.210 align:middle line:90%
OK.

00:28:34.210 --> 00:28:36.070 align:middle line:90%
So let's talk about bonds now.

00:28:36.070 --> 00:28:39.510 align:middle line:84%
We're going to
start pricing bonds.

00:28:39.510 --> 00:28:44.150 align:middle line:84%
So bonds differ along
many dimensions,

00:28:44.150 --> 00:28:46.790 align:middle line:84%
but one of them that's
very important for bones

00:28:46.790 --> 00:28:49.640 align:middle line:84%
is maturity the n
that I had there

00:28:49.640 --> 00:28:53.120 align:middle line:90%
in the previous expression.

00:28:53.120 --> 00:28:57.250 align:middle line:84%
So maturity means, essentially,
how long the bond lasts.

00:28:57.250 --> 00:28:59.510 align:middle line:84%
When does it pay you
back the principal?

00:28:59.510 --> 00:29:02.150 align:middle line:84%
The bonds typically pay
coupons, and then there

00:29:02.150 --> 00:29:04.910 align:middle line:84%
is a final payment, which we
call face value of the bond

00:29:04.910 --> 00:29:06.000 align:middle line:90%
or something like that.

00:29:06.000 --> 00:29:09.590 align:middle line:84%
And when that final
payment takes place,

00:29:09.590 --> 00:29:12.530 align:middle line:90%
that's a maturity of a bond.

00:29:12.530 --> 00:29:16.000 align:middle line:84%
So a bond that promises to make
a $1,000 final payment in six

00:29:16.000 --> 00:29:18.365 align:middle line:84%
months has a maturity
of six months.

00:29:18.365 --> 00:29:21.080 align:middle line:90%


00:29:21.080 --> 00:29:25.460 align:middle line:84%
A bond that promises to pay $100
for 20 years and then $1,000--

00:29:25.460 --> 00:29:28.930 align:middle line:84%
a final payment in 20 years
has a maturity of 20 years.

00:29:28.930 --> 00:29:30.430 align:middle line:84%
Maturity is different
from duration.

00:29:30.430 --> 00:29:32.597 align:middle line:84%
I don't think I'm going to
talk about duration here,

00:29:32.597 --> 00:29:34.790 align:middle line:84%
but that's maturity,
just when it's

00:29:34.790 --> 00:29:39.560 align:middle line:90%
the final payment of a loan--

00:29:39.560 --> 00:29:42.460 align:middle line:90%
of a bond?

00:29:42.460 --> 00:29:44.020 align:middle line:90%
Bonds of different maturities.

00:29:44.020 --> 00:29:46.930 align:middle line:84%
Each have a price and an
associated interest rate.

00:29:46.930 --> 00:29:48.550 align:middle line:84%
We're going to look
at those things.

00:29:48.550 --> 00:29:52.750 align:middle line:84%
And the associated interest rate
is called the yield to maturity,

00:29:52.750 --> 00:29:55.515 align:middle line:90%
or simply the yield of a bond.

00:29:55.515 --> 00:29:58.140 align:middle line:84%
This is terminology, but we are
going to calculate these things

00:29:58.140 --> 00:30:00.190 align:middle line:90%
later on.

00:30:00.190 --> 00:30:03.610 align:middle line:84%
The relationship between
maturity and yield

00:30:03.610 --> 00:30:05.440 align:middle line:90%
is called the yield curve.

00:30:05.440 --> 00:30:06.820 align:middle line:90%
Very important concept.

00:30:06.820 --> 00:30:08.870 align:middle line:84%
Big fuss about the
yield curve these days.

00:30:08.870 --> 00:30:11.840 align:middle line:84%
I'll talk a little
bit more about that.

00:30:11.840 --> 00:30:15.080 align:middle line:84%
Or sometimes it's called the
term structure of interest rate.

00:30:15.080 --> 00:30:19.560 align:middle line:84%
Term, in the language of
bonds, is really maturity.

00:30:19.560 --> 00:30:22.760 align:middle line:84%
So term structure of interest
rate really tells you what is

00:30:22.760 --> 00:30:26.660 align:middle line:84%
the yield in a 1-year bond,
2-year bond, 3-year bond, 4-,

00:30:26.660 --> 00:30:27.470 align:middle line:90%
5-, 6-, 7-.

00:30:27.470 --> 00:30:31.340 align:middle line:84%
You plot them, and
that gives you a curve.

00:30:31.340 --> 00:30:35.678 align:middle line:90%
So for example, look at those--

00:30:35.678 --> 00:30:37.220 align:middle line:84%
these are two
different yield curves.

00:30:37.220 --> 00:30:43.670 align:middle line:84%
This is November 2000
and this is June 2001.

00:30:43.670 --> 00:30:48.750 align:middle line:84%
So this tells you what the
yield is on a 3-month bond.

00:30:48.750 --> 00:30:51.020 align:middle line:84%
So a bond that matures
in three months.

00:30:51.020 --> 00:30:55.780 align:middle line:84%
On a 6-month bond, so on and
so forth, up to 30-year bonds.

00:30:55.780 --> 00:30:57.530 align:middle line:84%
What is the big
difference between these--

00:30:57.530 --> 00:30:59.360 align:middle line:84%
what do you think
happened here in between?

00:30:59.360 --> 00:31:01.550 align:middle line:84%
Notice that these two
curves are more or less

00:31:01.550 --> 00:31:04.190 align:middle line:84%
the same long-term
interest rate,

00:31:04.190 --> 00:31:06.290 align:middle line:84%
but they have very different--
these curves-- this

00:31:06.290 --> 00:31:09.420 align:middle line:84%
is a very steep curve and this
is a very flat or even inverted

00:31:09.420 --> 00:31:09.920 align:middle line:90%
curve.

00:31:09.920 --> 00:31:12.810 align:middle line:90%


00:31:12.810 --> 00:31:17.420 align:middle line:84%
What do you think may have
happened there between November

00:31:17.420 --> 00:31:19.848 align:middle line:90%
2000 and June 2001?

00:31:19.848 --> 00:31:21.640 align:middle line:84%
AUDIENCE: People changed
their expectations

00:31:21.640 --> 00:31:22.330 align:middle line:90%
about interest rates.

00:31:22.330 --> 00:31:23.330 align:middle line:90%
RICARDO CABALLERO: Yeah.

00:31:23.330 --> 00:31:24.190 align:middle line:90%
That's true.

00:31:24.190 --> 00:31:26.230 align:middle line:90%
That's for sure true about that.

00:31:26.230 --> 00:31:28.120 align:middle line:90%
But look also that--

00:31:28.120 --> 00:31:30.280 align:middle line:84%
but that these
three months, there

00:31:30.280 --> 00:31:32.240 align:middle line:84%
is very little uncertainty
about three months.

00:31:32.240 --> 00:31:34.190 align:middle line:90%
It was a lot lower than that.

00:31:34.190 --> 00:31:36.243 align:middle line:84%
So yes, people change
their expectations,

00:31:36.243 --> 00:31:38.410 align:middle line:84%
but why do you think they
change their expectations?

00:31:38.410 --> 00:31:42.440 align:middle line:90%


00:31:42.440 --> 00:31:45.440 align:middle line:84%
AUDIENCE: [INAUDIBLE]
rising [INAUDIBLE]

00:31:45.440 --> 00:31:47.690 align:middle line:84%
RICARDO CABALLERO: Rising
inflation from here to here.

00:31:47.690 --> 00:31:50.553 align:middle line:84%
These are nominal
interest rates.

00:31:50.553 --> 00:31:52.970 align:middle line:84%
Up to now, we've been talking
about nominal interest rate.

00:31:52.970 --> 00:31:56.510 align:middle line:90%


00:31:56.510 --> 00:32:00.290 align:middle line:84%
What happens here is there
was a mini-recession,

00:32:00.290 --> 00:32:03.240 align:middle line:90%
so the Fed cut interest rates.

00:32:03.240 --> 00:32:05.370 align:middle line:84%
When you are in
recessions, the curve

00:32:05.370 --> 00:32:10.240 align:middle line:84%
tends to look like this because
the central bank is cutting

00:32:10.240 --> 00:32:12.550 align:middle line:84%
interest rates in
the short-run to deal

00:32:12.550 --> 00:32:13.990 align:middle line:90%
with the current recession.

00:32:13.990 --> 00:32:15.880 align:middle line:84%
What happened 30 years
from now has nothing

00:32:15.880 --> 00:32:17.380 align:middle line:84%
to do with the
business cycle today,

00:32:17.380 --> 00:32:19.540 align:middle line:84%
so that interest rate
doesn't need to move a lot.

00:32:19.540 --> 00:32:22.270 align:middle line:84%
But the Fed is bringing
interest rates down a lot

00:32:22.270 --> 00:32:23.740 align:middle line:90%
in the front end.

00:32:23.740 --> 00:32:26.890 align:middle line:84%
So that's a typical shape
of a curve in a recession.

00:32:26.890 --> 00:32:29.770 align:middle line:84%
That's a typical
shape of a curve

00:32:29.770 --> 00:32:31.780 align:middle line:84%
in the opposite situation
where the inflation is

00:32:31.780 --> 00:32:32.650 align:middle line:90%
too high and so on.

00:32:32.650 --> 00:32:33.550 align:middle line:90%
Because what happens?

00:32:33.550 --> 00:32:35.290 align:middle line:84%
The Fed is trying
to-- the Fed really

00:32:35.290 --> 00:32:37.630 align:middle line:84%
controls the very
front end of the curve.

00:32:37.630 --> 00:32:39.880 align:middle line:84%
That's what the Fed really
controls-- the central bank

00:32:39.880 --> 00:32:41.950 align:middle line:84%
in general, but the Fed, they
control the very front end

00:32:41.950 --> 00:32:43.690 align:middle line:84%
of the curve because they're
setting the very short-term

00:32:43.690 --> 00:32:44.750 align:middle line:90%
interest rate.

00:32:44.750 --> 00:32:46.300 align:middle line:84%
So this is a situation
where they're

00:32:46.300 --> 00:32:49.360 align:middle line:84%
tighten-- the monetary policy
is very tight because they

00:32:49.360 --> 00:32:52.635 align:middle line:84%
have a situation of
overheating in the economy.

00:32:52.635 --> 00:32:54.260 align:middle line:84%
And in fact, they
got too carried away.

00:32:54.260 --> 00:32:56.885 align:middle line:84%
That's the reason that we
ended up in a recession here.

00:32:56.885 --> 00:32:57.385 align:middle line:90%
OK.

00:32:57.385 --> 00:33:00.022 align:middle line:90%


00:33:00.022 --> 00:33:01.355 align:middle line:90%
How do you think it looks today?

00:33:01.355 --> 00:33:06.330 align:middle line:90%


00:33:06.330 --> 00:33:09.730 align:middle line:84%
Do you think it looks more
like this or more like that?

00:33:09.730 --> 00:33:11.305 align:middle line:90%
Is inflation low or high today?

00:33:11.305 --> 00:33:14.190 align:middle line:90%


00:33:14.190 --> 00:33:14.880 align:middle line:90%
High.

00:33:14.880 --> 00:33:15.930 align:middle line:90%
I mean, that's a problem.

00:33:15.930 --> 00:33:17.670 align:middle line:84%
The Fed is trying to
hike interest rates.

00:33:17.670 --> 00:33:21.180 align:middle line:84%
Now recently, because of the
mess in the banking sector,

00:33:21.180 --> 00:33:22.800 align:middle line:84%
then expectations
of interest rates

00:33:22.800 --> 00:33:26.100 align:middle line:84%
have begun to decline a
little, but the situation

00:33:26.100 --> 00:33:27.120 align:middle line:90%
was very inverted.

00:33:27.120 --> 00:33:28.710 align:middle line:90%
Here you are.

00:33:28.710 --> 00:33:30.790 align:middle line:90%
The green line is today.

00:33:30.790 --> 00:33:32.130 align:middle line:90%
OK, so it's very inverted.

00:33:32.130 --> 00:33:35.600 align:middle line:90%


00:33:35.600 --> 00:33:38.130 align:middle line:90%
A year ago, it looked like that.

00:33:38.130 --> 00:33:40.490 align:middle line:84%
So you see, the longer
hasn't changed much,

00:33:40.490 --> 00:33:42.440 align:middle line:84%
but a year ago,
there was no sense

00:33:42.440 --> 00:33:46.468 align:middle line:84%
that inflation was getting
so much out of line.

00:33:46.468 --> 00:33:48.010 align:middle line:84%
It happened a little
later than that.

00:33:48.010 --> 00:33:52.127 align:middle line:84%
There was some concern that
interest rates would rise,

00:33:52.127 --> 00:33:54.460 align:middle line:84%
but now it's very clear that
the economy is overheating.

00:33:54.460 --> 00:33:59.540 align:middle line:84%
And this-- I should have plot
you something for a month ago,

00:33:59.540 --> 00:34:01.030 align:middle line:90%
it would have been even steeper.

00:34:01.030 --> 00:34:03.340 align:middle line:90%
OK.

00:34:03.340 --> 00:34:03.880 align:middle line:90%
Anyways.

00:34:03.880 --> 00:34:06.710 align:middle line:84%
But that's because the Fed is
trying to slow down the economy.

00:34:06.710 --> 00:34:07.840 align:middle line:90%
It's hiking interest rates.

00:34:07.840 --> 00:34:10.510 align:middle line:84%
That's the reason the curve
is very, very inverted today.

00:34:10.510 --> 00:34:13.300 align:middle line:90%


00:34:13.300 --> 00:34:14.800 align:middle line:90%
So let me calculate these rates.

00:34:14.800 --> 00:34:15.760 align:middle line:90%
How do we go about it?

00:34:15.760 --> 00:34:17.260 align:middle line:84%
So the first thing
we're going to do

00:34:17.260 --> 00:34:19.510 align:middle line:84%
is we're going to use the
expected present discounted

00:34:19.510 --> 00:34:24.070 align:middle line:84%
value formula to calculate
the price of a bond.

00:34:24.070 --> 00:34:27.460 align:middle line:84%
And then we want to start
doing it for different bonds,

00:34:27.460 --> 00:34:30.750 align:middle line:84%
and we're going to
construct the yield curve.

00:34:30.750 --> 00:34:36.620 align:middle line:84%
So suppose you have a bond that
pays $100, nothing in between,

00:34:36.620 --> 00:34:38.400 align:middle line:90%
$100 one year from now.

00:34:38.400 --> 00:34:41.770 align:middle line:84%
So this is a bond with
maturity, 1-year maturity.

00:34:41.770 --> 00:34:45.790 align:middle line:84%
I'm going to call that
bond with 1-year maturity--

00:34:45.790 --> 00:34:50.020 align:middle line:84%
the price of a bond with a
1-year maturity at time t P1t.

00:34:50.020 --> 00:34:51.400 align:middle line:90%
Well, that's easy to calculate.

00:34:51.400 --> 00:34:53.590 align:middle line:84%
It's expected present
discounted value for you.

00:34:53.590 --> 00:34:55.449 align:middle line:84%
You have the interest
rate, whatever it--

00:34:55.449 --> 00:34:58.660 align:middle line:84%
say 1-year interest rate, then I
know that the price of the bond

00:34:58.660 --> 00:35:01.370 align:middle line:84%
is 100 divided by 1
plus the interest rate,

00:35:01.370 --> 00:35:04.820 align:middle line:90%
the 1-year interest rate today.

00:35:04.820 --> 00:35:05.540 align:middle line:90%
That's the price.

00:35:05.540 --> 00:35:06.840 align:middle line:84%
That's the expected
discounted value.

00:35:06.840 --> 00:35:08.340 align:middle line:84%
So I tell you--
what I'm showing you

00:35:08.340 --> 00:35:12.260 align:middle line:84%
is the relationship between
interest rates and prices.

00:35:12.260 --> 00:35:13.340 align:middle line:90%
Our price of a bond.

00:35:13.340 --> 00:35:18.290 align:middle line:84%
The price of that bond is just
100 divided by 1 plus the--

00:35:18.290 --> 00:35:20.510 align:middle line:84%
1 plus-- the 1-year
interest rate today.

00:35:20.510 --> 00:35:23.610 align:middle line:90%


00:35:23.610 --> 00:35:27.120 align:middle line:84%
So important observation is
that the price of a 1-year bond

00:35:27.120 --> 00:35:31.170 align:middle line:84%
varies inversely with the
current 1-year nominal interest

00:35:31.170 --> 00:35:31.720 align:middle line:90%
rate.

00:35:31.720 --> 00:35:34.570 align:middle line:90%
This is all nominal.

00:35:34.570 --> 00:35:36.490 align:middle line:84%
Why is that inverse
relationship?

00:35:36.490 --> 00:35:39.490 align:middle line:84%
Why is it the price of a 1-year
bond is inversely related

00:35:39.490 --> 00:35:40.900 align:middle line:90%
to the 1-year interest rate?

00:35:40.900 --> 00:35:44.750 align:middle line:90%


00:35:44.750 --> 00:35:47.050 align:middle line:84%
In other words,
I'm asking, what do

00:35:47.050 --> 00:35:49.450 align:middle line:84%
you think happens to the
price as the nominal interest

00:35:49.450 --> 00:35:50.620 align:middle line:90%
rate rises?

00:35:50.620 --> 00:35:55.010 align:middle line:84%
And why do you think that's
what happens to the price?

00:35:55.010 --> 00:35:56.998 align:middle line:84%
Well, the first question
doesn't have a--

00:35:56.998 --> 00:35:58.790 align:middle line:84%
I mean, it's very easy,
you know the answer

00:35:58.790 --> 00:35:59.707 align:middle line:90%
to the first question.

00:35:59.707 --> 00:36:01.110 align:middle line:90%
What happens if i goes up?

00:36:01.110 --> 00:36:04.100 align:middle line:84%
Well, it's obvious that this
price comes down, but why?

00:36:04.100 --> 00:36:08.500 align:middle line:90%


00:36:08.500 --> 00:36:11.950 align:middle line:84%
And use the concepts
we have developed here.

00:36:11.950 --> 00:36:15.760 align:middle line:84%
Remember, we spent like
20 minutes in one slide.

00:36:15.760 --> 00:36:17.530 align:middle line:90%
Use that slide for that answer.

00:36:17.530 --> 00:36:22.800 align:middle line:90%


00:36:22.800 --> 00:36:26.220 align:middle line:84%
Hint-- this $100 you
are not receiving today,

00:36:26.220 --> 00:36:28.710 align:middle line:84%
you are receiving
a year from now.

00:36:28.710 --> 00:36:31.530 align:middle line:84%
What happens with $1
received a year from now?

00:36:31.530 --> 00:36:35.250 align:middle line:84%
What is the value of a dollar
received one year from now

00:36:35.250 --> 00:36:36.375 align:middle line:90%
when the interest is high?

00:36:36.375 --> 00:36:39.150 align:middle line:90%


00:36:39.150 --> 00:36:42.660 align:middle line:84%
It's low because you'd much
rather have the dollar today,

00:36:42.660 --> 00:36:46.180 align:middle line:84%
invest it, and get this
big return on the dollar.

00:36:46.180 --> 00:36:49.770 align:middle line:84%
That means, naturally, a bond
that is paying you $100 tomorrow

00:36:49.770 --> 00:36:52.985 align:middle line:84%
is going to be worth less when
the interest rate is very high.

00:36:52.985 --> 00:36:54.360 align:middle line:84%
It's going to be
worth less today

00:36:54.360 --> 00:36:55.350 align:middle line:90%
when the interest is very high.

00:36:55.350 --> 00:36:58.080 align:middle line:84%
You'd rather have the money
today, invest it in the interest

00:36:58.080 --> 00:37:00.270 align:middle line:90%
rate and get the interest rate.

00:37:00.270 --> 00:37:06.780 align:middle line:84%
And I need to invest 1 over 1
plus i1t dollars to get $100.

00:37:06.780 --> 00:37:10.380 align:middle line:90%
That's another way of saying it.

00:37:10.380 --> 00:37:15.110 align:middle line:84%
What about the bond that
pays $100 in two years?

00:37:15.110 --> 00:37:17.910 align:middle line:84%
Well, I need to
discount that by this,

00:37:17.910 --> 00:37:20.640 align:middle line:84%
which is-- it's a product
of the two interest rate.

00:37:20.640 --> 00:37:24.170 align:middle line:84%
And since I don't know what the
1-year rate will be one year

00:37:24.170 --> 00:37:26.413 align:middle line:84%
from now, I have to use
expectation here rather than

00:37:26.413 --> 00:37:27.080 align:middle line:90%
the actual rate.

00:37:27.080 --> 00:37:28.340 align:middle line:90%
But look at the notation.

00:37:28.340 --> 00:37:34.910 align:middle line:84%
I'm calling P2t-- $P2t,
the price of a 2-year bond,

00:37:34.910 --> 00:37:39.090 align:middle line:84%
a bond with maturity of
two years, as of time t.

00:37:39.090 --> 00:37:42.100 align:middle line:84%
And this is a bond
that has no coupons.

00:37:42.100 --> 00:37:47.850 align:middle line:84%
Yes, pays you $100 at
the end of the two years.

00:37:47.850 --> 00:37:53.640 align:middle line:84%
Now note that this price is
inversely related to both

00:37:53.640 --> 00:37:58.890 align:middle line:84%
the 1-year rate today and the
expectation of the 1-year rate

00:37:58.890 --> 00:38:01.520 align:middle line:90%
one year from now.

00:38:01.520 --> 00:38:05.650 align:middle line:84%
If either one of these goes up,
the bond is worthless today.

00:38:05.650 --> 00:38:11.780 align:middle line:84%
You discount more $1
received two years from now.

00:38:11.780 --> 00:38:13.100 align:middle line:90%
I don't care which one--

00:38:13.100 --> 00:38:16.550 align:middle line:84%
either of them that
goes up is bad news

00:38:16.550 --> 00:38:18.020 align:middle line:90%
for the price of a bond.

00:38:18.020 --> 00:38:24.440 align:middle line:90%


00:38:24.440 --> 00:38:25.050 align:middle line:90%
It's clear?

00:38:25.050 --> 00:38:28.340 align:middle line:90%


00:38:28.340 --> 00:38:30.440 align:middle line:90%
So there is an alternative.

00:38:30.440 --> 00:38:33.640 align:middle line:84%
So this is the way you
price bonds using just

00:38:33.640 --> 00:38:37.580 align:middle line:84%
expected discounted
value approach.

00:38:37.580 --> 00:38:39.790 align:middle line:84%
Now it turns out that in
practice, a lot of the asset

00:38:39.790 --> 00:38:42.130 align:middle line:84%
pricing is done by
arbitrage, meaning

00:38:42.130 --> 00:38:46.480 align:middle line:84%
you compare different assets,
and that have similar risks,

00:38:46.480 --> 00:38:48.820 align:middle line:84%
they should give you more
or less the same return.

00:38:48.820 --> 00:38:52.870 align:middle line:84%
That's what you-- so let
me do this arbitrage thing.

00:38:52.870 --> 00:38:55.950 align:middle line:84%
Suppose you're considering
investing $1 for one year.

00:38:55.950 --> 00:38:56.950 align:middle line:90%
So that's your decision.

00:38:56.950 --> 00:38:57.992 align:middle line:90%
I'm going to invest one--

00:38:57.992 --> 00:39:02.060 align:middle line:84%
I have a dollar, which I
want to invest for one year.

00:39:02.060 --> 00:39:05.090 align:middle line:84%
But I have two
options to do that.

00:39:05.090 --> 00:39:08.840 align:middle line:84%
I can invest $1
in a 1-year bond.

00:39:08.840 --> 00:39:11.710 align:middle line:84%
I know exactly what I'm
going to get in that bond.

00:39:11.710 --> 00:39:17.440 align:middle line:84%
Or I can invest in a 2-year
bond and sell it at the end

00:39:17.440 --> 00:39:18.640 align:middle line:90%
of the first year.

00:39:18.640 --> 00:39:23.465 align:middle line:84%
Those are two ways of
investing for one year.

00:39:23.465 --> 00:39:25.840 align:middle line:84%
Arbitrage has to be compared
over the same period of time

00:39:25.840 --> 00:39:26.260 align:middle line:90%
and everything.

00:39:26.260 --> 00:39:27.843 align:middle line:84%
It's not the return
of a bond that you

00:39:27.843 --> 00:39:30.760 align:middle line:84%
hold for 10 years versus one
that you hold for one year.

00:39:30.760 --> 00:39:32.780 align:middle line:84%
It has to be something
a similar investment.

00:39:32.780 --> 00:39:34.870 align:middle line:84%
Suppose I need to
invest for one year.

00:39:34.870 --> 00:39:38.640 align:middle line:90%


00:39:38.640 --> 00:39:39.140 align:middle line:90%
OK.

00:39:39.140 --> 00:39:41.750 align:middle line:84%
Then if I have these
two bonds, the option

00:39:41.750 --> 00:39:44.822 align:middle line:84%
is not buy one or
the other and then

00:39:44.822 --> 00:39:46.280 align:middle line:84%
hold to maturity
because that would

00:39:46.280 --> 00:39:48.655 align:middle line:84%
be comparing an investment of
one year with an investment

00:39:48.655 --> 00:39:49.550 align:middle line:90%
of two years.

00:39:49.550 --> 00:39:52.310 align:middle line:84%
I need to compare the
strategies of getting

00:39:52.310 --> 00:39:54.240 align:middle line:90%
my return in one year.

00:39:54.240 --> 00:39:57.320 align:middle line:84%
In the 1-year bond that's
trivial because I get my return

00:39:57.320 --> 00:39:59.120 align:middle line:84%
at the end at the
maturity of the bond.

00:39:59.120 --> 00:40:02.210 align:middle line:84%
In the 2-year bond, it means I
need to sell it in between after

00:40:02.210 --> 00:40:03.290 align:middle line:90%
one year.

00:40:03.290 --> 00:40:05.870 align:middle line:84%
So those are the two
strategies I want to compare.

00:40:05.870 --> 00:40:08.630 align:middle line:90%
And since I'm not--

00:40:08.630 --> 00:40:11.598 align:middle line:84%
considering risk here
as a central element,

00:40:11.598 --> 00:40:13.640 align:middle line:84%
those two strategies are
going to have to give me

00:40:13.640 --> 00:40:16.120 align:middle line:90%
the same expected return.

00:40:16.120 --> 00:40:17.050 align:middle line:90%
That's arbitrage.

00:40:17.050 --> 00:40:19.430 align:middle line:90%
That's what we call arbitrage.

00:40:19.430 --> 00:40:25.910 align:middle line:84%
The two strategies have to give
me the same expected return.

00:40:25.910 --> 00:40:30.350 align:middle line:84%
So what do we get
from this strategies?

00:40:30.350 --> 00:40:32.400 align:middle line:84%
Well, if I go through
the 1-year bond,

00:40:32.400 --> 00:40:36.080 align:middle line:84%
I know I'm going to get my
dollar times 1 plus i1t.

00:40:36.080 --> 00:40:39.950 align:middle line:84%
That's what I get for one year--
out of investing $1 in a 1-year

00:40:39.950 --> 00:40:40.580 align:middle line:90%
bond.

00:40:40.580 --> 00:40:43.220 align:middle line:84%
If I go through the
2-year bond strategy,

00:40:43.220 --> 00:40:45.080 align:middle line:84%
buy it and sell it at
the end of the year,

00:40:45.080 --> 00:40:46.520 align:middle line:90%
then I'm going to get--

00:40:46.520 --> 00:40:52.670 align:middle line:84%
I invest $1 today,
I'm going to pay P2t--

00:40:52.670 --> 00:40:55.700 align:middle line:84%
that's what I pay today
for a 2-year bond,

00:40:55.700 --> 00:40:57.530 align:middle line:84%
that's what I pay here
for a 2-year bond.

00:40:57.530 --> 00:41:02.660 align:middle line:84%
And I expect to get the price of
a 1-year bond one year from now.

00:41:02.660 --> 00:41:06.530 align:middle line:84%
I mean, the 2-year bond will be
a 1-year bond after a year has

00:41:06.530 --> 00:41:08.120 align:middle line:90%
passed.

00:41:08.120 --> 00:41:10.910 align:middle line:84%
It's a 2-year bond today,
but after one year,

00:41:10.910 --> 00:41:13.470 align:middle line:84%
it's going to have only
one year to mature.

00:41:13.470 --> 00:41:17.810 align:middle line:84%
So that's the reason the price
I need to forecast is the price

00:41:17.810 --> 00:41:20.210 align:middle line:84%
of a 1-year bond
one year from now.

00:41:20.210 --> 00:41:22.430 align:middle line:90%
That's what this is here.

00:41:22.430 --> 00:41:24.020 align:middle line:84%
And that's my return
on this strategy

00:41:24.020 --> 00:41:27.900 align:middle line:84%
because I'm going to pay
this today, these dollars,

00:41:27.900 --> 00:41:31.020 align:middle line:84%
and I expect to get
that one year from now.

00:41:31.020 --> 00:41:35.835 align:middle line:84%
OK so arbitrage means I
need to set these to equal.

00:41:35.835 --> 00:41:42.280 align:middle line:90%


00:41:42.280 --> 00:41:47.643 align:middle line:84%
So that means I have to get the
same return with two strategies.

00:41:47.643 --> 00:41:49.060 align:middle line:84%
That means I'm
investing the same.

00:41:49.060 --> 00:41:52.980 align:middle line:84%
So you only need to
compare the returns.

00:41:52.980 --> 00:41:57.310 align:middle line:90%
This needs to be equal to that.

00:41:57.310 --> 00:42:00.100 align:middle line:90%
That's what I have here.

00:42:00.100 --> 00:42:04.530 align:middle line:84%
Which tells you that you are
solving from here that the price

00:42:04.530 --> 00:42:08.610 align:middle line:84%
of a 2-year bond at time t is
equal to the expected price

00:42:08.610 --> 00:42:13.960 align:middle line:84%
of a 1-year bond at t plus 1
discounted by 1 plus the 1-year

00:42:13.960 --> 00:42:16.770 align:middle line:90%
interest rate.

00:42:16.770 --> 00:42:18.870 align:middle line:90%
This was like my cash flow--

00:42:18.870 --> 00:42:20.830 align:middle line:84%
my cash flow now is
not the cash flow--

00:42:20.830 --> 00:42:23.340 align:middle line:84%
it's just the price I'm going
to get a price for that asset.

00:42:23.340 --> 00:42:26.880 align:middle line:84%
That's like the z's
I had in my formula.

00:42:26.880 --> 00:42:30.660 align:middle line:84%
And for a 1-year strategy, I
only needed to worry about the z

00:42:30.660 --> 00:42:31.690 align:middle line:90%
plus 1.

00:42:31.690 --> 00:42:34.780 align:middle line:90%
There was no dividend at day 0.

00:42:34.780 --> 00:42:37.110 align:middle line:90%
And that's exactly that formula.

00:42:37.110 --> 00:42:43.730 align:middle line:84%
But notice that at t
plus 1, that will hold.

00:42:43.730 --> 00:42:44.968 align:middle line:90%
So at t plus 1--

00:42:44.968 --> 00:42:46.760 align:middle line:84%
I'm at t plus 1, I
don't need expectations.

00:42:46.760 --> 00:42:51.470 align:middle line:84%
I know that P1t plus 1 will be
equal to 100 divided by 1 plus

00:42:51.470 --> 00:42:54.340 align:middle line:84%
i1, the 1-year
rate, at t plus 1.

00:42:54.340 --> 00:42:57.830 align:middle line:84%
Therefore, the
expected is something

00:42:57.830 --> 00:42:59.090 align:middle line:90%
like this, approximately.

00:42:59.090 --> 00:43:02.490 align:middle line:84%
The expected price is
something like that.

00:43:02.490 --> 00:43:05.890 align:middle line:84%
I expect-- I mean, this
will be-- without the e,

00:43:05.890 --> 00:43:09.400 align:middle line:84%
will be the price of this
1-year bond at t plus 1.

00:43:09.400 --> 00:43:12.020 align:middle line:84%
I don't know exactly what the
interest rate will be next year,

00:43:12.020 --> 00:43:15.310 align:middle line:84%
so I have-- the best I can do
is have an expectation-- that's

00:43:15.310 --> 00:43:18.400 align:middle line:90%
my expectation, approximately.

00:43:18.400 --> 00:43:23.120 align:middle line:84%
But now I can stick
this expression in here.

00:43:23.120 --> 00:43:27.770 align:middle line:84%
I have this I'm going out
and I can stick that in there

00:43:27.770 --> 00:43:29.940 align:middle line:90%
and I get this expression.

00:43:29.940 --> 00:43:32.810 align:middle line:84%
So that's the price
for the 2-year bond.

00:43:32.810 --> 00:43:33.920 align:middle line:90%
Do you recognize this?

00:43:33.920 --> 00:43:37.805 align:middle line:90%


00:43:37.805 --> 00:43:38.555 align:middle line:90%
You saw it before.

00:43:38.555 --> 00:43:46.970 align:middle line:90%


00:43:46.970 --> 00:43:48.740 align:middle line:84%
That's the same
expression that we

00:43:48.740 --> 00:43:51.260 align:middle line:84%
got when we used the expected
present discounted value

00:43:51.260 --> 00:43:53.430 align:middle line:90%
formula.

00:43:53.430 --> 00:43:55.980 align:middle line:84%
We said we're going to
go-- say $100 years--

00:43:55.980 --> 00:43:58.290 align:middle line:84%
100 years-- two
years from now, I

00:43:58.290 --> 00:44:00.450 align:middle line:84%
know that discount factor
for that is 1 over 1

00:44:00.450 --> 00:44:05.460 align:middle line:84%
plus i1t times 1 plus
i1t plus 1 expected.

00:44:05.460 --> 00:44:08.040 align:middle line:90%
Well, that's what I got.

00:44:08.040 --> 00:44:09.460 align:middle line:90%
Get some arbitrage.

00:44:09.460 --> 00:44:10.760 align:middle line:90%
OK.

00:44:10.760 --> 00:44:11.990 align:middle line:90%
From an arbitrage logic.

00:44:11.990 --> 00:44:15.830 align:middle line:90%
This is used a lot in finance.

00:44:15.830 --> 00:44:17.600 align:middle line:84%
I'm going to say
something complicated,

00:44:17.600 --> 00:44:23.290 align:middle line:90%
but just ignore it if it's--

00:44:23.290 --> 00:44:26.310 align:middle line:90%


00:44:26.310 --> 00:44:29.470 align:middle line:84%
it's not relevant for
the quiz or anything.

00:44:29.470 --> 00:44:33.440 align:middle line:84%
But there is a big debate
in the US today about--

00:44:33.440 --> 00:44:42.000 align:middle line:84%
not big debate, a big concern
about the US Treasury debt

00:44:42.000 --> 00:44:43.950 align:middle line:84%
because there is a
debt ceiling, meaning

00:44:43.950 --> 00:44:46.620 align:middle line:84%
there is a maximum amount
that the government can--

00:44:46.620 --> 00:44:52.090 align:middle line:84%
of debt they can
issue, and that ceiling

00:44:52.090 --> 00:44:54.640 align:middle line:84%
has been moved over
time, but every time we

00:44:54.640 --> 00:44:57.700 align:middle line:84%
get close to a deadline, when
this needs to be agreed again,

00:44:57.700 --> 00:45:00.974 align:middle line:84%
there is a concern and there's
negotiations and so on, and--

00:45:00.974 --> 00:45:03.700 align:middle line:90%


00:45:03.700 --> 00:45:06.310 align:middle line:84%
well, I mean, everyone
at this moment at least

00:45:06.310 --> 00:45:10.390 align:middle line:84%
thinks that, as in every
instance in the past,

00:45:10.390 --> 00:45:13.000 align:middle line:84%
they're going to reach some
sort of agreement the day

00:45:13.000 --> 00:45:15.920 align:middle line:90%
before of the deadline or not.

00:45:15.920 --> 00:45:18.550 align:middle line:84%
But if they don't,
and there is a mess,

00:45:18.550 --> 00:45:20.320 align:middle line:90%
this is huge for finance.

00:45:20.320 --> 00:45:23.410 align:middle line:84%
It's huge for finance because
US Treasury bonds, especially

00:45:23.410 --> 00:45:26.590 align:middle line:84%
short-term bonds, are used
for pricing everything

00:45:26.590 --> 00:45:28.430 align:middle line:90%
through arbitrage and so on.

00:45:28.430 --> 00:45:30.070 align:middle line:90%
So you get a mess there.

00:45:30.070 --> 00:45:32.650 align:middle line:84%
That's a mess in every
single financial market.

00:45:32.650 --> 00:45:36.640 align:middle line:84%
You wouldn't know how to price
many financial assets, actually.

00:45:36.640 --> 00:45:38.020 align:middle line:90%
So it would be a disaster.

00:45:38.020 --> 00:45:42.340 align:middle line:84%
But the reason I
mention this here

00:45:42.340 --> 00:45:44.770 align:middle line:84%
is because, again,
lots of prices

00:45:44.770 --> 00:45:47.140 align:middle line:84%
are priced in
reference-- in finance

00:45:47.140 --> 00:45:49.610 align:middle line:84%
are priced in reference,
especially derivatives, options,

00:45:49.610 --> 00:45:52.880 align:middle line:84%
and stuff like that, you price
them relative to something

00:45:52.880 --> 00:45:54.660 align:middle line:90%
using this type of logic.

00:45:54.660 --> 00:45:56.390 align:middle line:84%
So if the thing
you use as a base,

00:45:56.390 --> 00:45:58.640 align:middle line:84%
as a reference becomes
highly unstable

00:45:58.640 --> 00:46:01.790 align:middle line:84%
and uncertain and risky,
then obviously everything

00:46:01.790 --> 00:46:04.420 align:middle line:84%
becomes very
complicated, very risky,

00:46:04.420 --> 00:46:09.790 align:middle line:84%
and financial markets do not
like risk, that's for sure.

00:46:09.790 --> 00:46:12.970 align:middle line:84%
Anyways, ignore that, that's
irrelevant for your quiz,

00:46:12.970 --> 00:46:15.220 align:middle line:84%
but that's the reason
this-- the whole discussion

00:46:15.220 --> 00:46:17.800 align:middle line:84%
can over the summer can
get to be very, very

00:46:17.800 --> 00:46:20.850 align:middle line:90%
tricky for finance.

00:46:20.850 --> 00:46:23.340 align:middle line:84%
So the yield to maturity--
remember I mentioned this

00:46:23.340 --> 00:46:27.750 align:middle line:84%
concept before-- of an
n-year bond is also--

00:46:27.750 --> 00:46:31.780 align:middle line:84%
whenever you hear the
3-year rate, it's that.

00:46:31.780 --> 00:46:34.390 align:middle line:90%
It's the yield to maturity.

00:46:34.390 --> 00:46:35.700 align:middle line:90%
A which is different from--

00:46:35.700 --> 00:46:37.350 align:middle line:90%
OK, let me tell you--

00:46:37.350 --> 00:46:40.050 align:middle line:84%
show you a formula that's
easy to explain, then.

00:46:40.050 --> 00:46:42.330 align:middle line:84%
And it's defined--
it's important--

00:46:42.330 --> 00:46:46.350 align:middle line:84%
as the constant annual interest
rate that makes the bond price

00:46:46.350 --> 00:46:50.010 align:middle line:84%
today equal to the present
discounted value or expected

00:46:50.010 --> 00:46:51.250 align:middle line:90%
discounted value.

00:46:51.250 --> 00:46:53.910 align:middle line:84%
So notice the
highlight there, it's

00:46:53.910 --> 00:46:56.730 align:middle line:84%
defined as the constant
annual interest

00:46:56.730 --> 00:47:00.240 align:middle line:84%
rate that makes the bond price
today equal to the present

00:47:00.240 --> 00:47:04.370 align:middle line:84%
discounted value of future
payments of the bond.

00:47:04.370 --> 00:47:10.510 align:middle line:84%
So, for example, in our
2-year bond, that's the price.

00:47:10.510 --> 00:47:12.450 align:middle line:90%
This is the price of the asset.

00:47:12.450 --> 00:47:14.400 align:middle line:90%
That we know the price.

00:47:14.400 --> 00:47:18.010 align:middle line:84%
We already got the price from
the previous slides of the bond,

00:47:18.010 --> 00:47:20.520 align:middle line:84%
which was based on the
short-term interest rate,

00:47:20.520 --> 00:47:23.790 align:middle line:84%
1-year interest rate, and our
forecast of the short-term--

00:47:23.790 --> 00:47:26.790 align:middle line:84%
the 1-year interest
rate one year from now.

00:47:26.790 --> 00:47:29.080 align:middle line:84%
I know that price,
take that as a number.

00:47:29.080 --> 00:47:32.250 align:middle line:84%
So then the yield
the yield to maturity

00:47:32.250 --> 00:47:35.790 align:middle line:84%
is calculated as that
constant interest rate--

00:47:35.790 --> 00:47:37.432 align:middle line:84%
constant-- how do I
see this constant?

00:47:37.432 --> 00:47:39.390 align:middle line:84%
Because, well, I'm using
the same interest rate

00:47:39.390 --> 00:47:41.490 align:middle line:84%
for the first period
and the second period,

00:47:41.490 --> 00:47:42.990 align:middle line:90%
and now I'm calling it i2t.

00:47:42.990 --> 00:47:45.510 align:middle line:84%
It's a 2-year interest
rate, but it's constant.

00:47:45.510 --> 00:47:48.730 align:middle line:84%
Constant doesn't mean that
it doesn't move over time.

00:47:48.730 --> 00:47:50.560 align:middle line:84%
It means I'm discounting
all the cash flows

00:47:50.560 --> 00:47:51.880 align:middle line:90%
as a constant interest rate.

00:47:51.880 --> 00:47:57.770 align:middle line:84%
It means I'm using
this equation.

00:47:57.770 --> 00:47:58.310 align:middle line:90%
OK.

00:47:58.310 --> 00:48:02.930 align:middle line:84%
So the yield to maturity is find
an interest rate that allows

00:48:02.930 --> 00:48:04.640 align:middle line:90%
me to use this constant thing--

00:48:04.640 --> 00:48:07.820 align:middle line:84%
constant-- assume--
use this formula

00:48:07.820 --> 00:48:10.820 align:middle line:84%
and get back the
same price as I got

00:48:10.820 --> 00:48:15.560 align:middle line:84%
by using the expected discounted
value or the arbitrage

00:48:15.560 --> 00:48:16.970 align:middle line:90%
or something like that.

00:48:16.970 --> 00:48:19.280 align:middle line:90%
So that's the definition.

00:48:19.280 --> 00:48:20.940 align:middle line:90%
You this price.

00:48:20.940 --> 00:48:23.360 align:middle line:84%
Now you look for that
interest rate that

00:48:23.360 --> 00:48:24.890 align:middle line:90%
allows you to match that price.

00:48:24.890 --> 00:48:27.510 align:middle line:90%


00:48:27.510 --> 00:48:28.740 align:middle line:90%
And that's called the yield.

00:48:28.740 --> 00:48:33.780 align:middle line:84%
That's the thing-- remember,
I plotted some curves.

00:48:33.780 --> 00:48:36.090 align:middle line:84%
Well, those interest
rates and those curves

00:48:36.090 --> 00:48:39.340 align:middle line:90%
were computed this way.

00:48:39.340 --> 00:48:42.850 align:middle line:84%
Now notice that we know
what this price is.

00:48:42.850 --> 00:48:45.400 align:middle line:84%
This price is, by the
expected discounted value

00:48:45.400 --> 00:48:49.760 align:middle line:84%
or the arbitrage approach, is
equal to 100 divided by this.

00:48:49.760 --> 00:48:51.670 align:middle line:84%
So I know that these
two things are--

00:48:51.670 --> 00:48:56.820 align:middle line:84%
this is equal to that, which
means that this denominator is

00:48:56.820 --> 00:48:58.660 align:middle line:90%
equal to that.

00:48:58.660 --> 00:49:01.420 align:middle line:84%
And that implies, for
a small interest rate,

00:49:01.420 --> 00:49:04.900 align:middle line:84%
that these two-year interest
rate is approximately equal

00:49:04.900 --> 00:49:07.510 align:middle line:84%
to the average of the
expected interest rate--

00:49:07.510 --> 00:49:08.320 align:middle line:90%
1-year rates.

00:49:08.320 --> 00:49:11.310 align:middle line:90%


00:49:11.310 --> 00:49:14.130 align:middle line:84%
So this is called actually
the expectation or hypothesis,

00:49:14.130 --> 00:49:14.890 align:middle line:90%
by the way.

00:49:14.890 --> 00:49:18.420 align:middle line:84%
Is that the 2-year rate
is approximately equal

00:49:18.420 --> 00:49:23.160 align:middle line:84%
to the average of the 1-year
rate this year plus the expected

00:49:23.160 --> 00:49:25.500 align:middle line:90%
1-year rate one year from now.

00:49:25.500 --> 00:49:30.130 align:middle line:90%


00:49:30.130 --> 00:49:31.910 align:middle line:90%
So that's an important concept.

00:49:31.910 --> 00:49:36.030 align:middle line:84%
I'm going to start from here
again in the next lecture.

00:49:36.030 --> 00:49:49.000 align:middle line:90%