- [Instructor] What we're going to do in this video
is talk a lot about money.
And in particular,
we're gonna talk about the market for money.
And this might seem a little bit counterintuitive,
because we're used to thinking
about the market in other things,
and we use money as a way to think about price,
we use money as a way to facilitate transactions.
But now, the market is money itself.
So the first question is,
how do we somehow come up with a cost of money?
And to help us with that,
I'll give you a little bit of a thought experiment.
Let's say that we had a very, very simple world
where you had two options.
You could have your cash money.
You could have a hundred dollars in cash, just like that.
Or, you could lend that hundred dollars to the government,
and the government would pay you back,
in a month, 101 dollars.
So your other option, we'll call that a bond,
a bond, which is really,
you're lending in this situation,
you're lending this money to the government.
Let's assume that it is risk-free,
that the government is good for the money.
You can also have bonds
where you're lending to other entities,
like states, or to corporations.
But let's say that this is a federal government bond,
and in one month,
it costs a hundred dollars.
It costs 100 dollars.
And in one month, in one month,
the government will pay back...
Government pays back 101 dollars.
So my question to you is,
if you decide, instead of buying this bond,
and then having the government pay you back
in a month for 101 dollars.
Instead of that, if you decide,
'Hey, you know what, that sounds interesting,
'but I just like the feel of cash.'
What is the opportunity cost of holding the cash?
Pause the video and think about that.
Well, if you decide to hold this cash
instead of buying this government bond,
instead of lending it to the government for that month,
you are foregoing one dollar.
So your opportunity cost right over here,
you could view it as one dollar over the month.
Or, if you think about it
in terms of how much money this is,
you have a one-percent opportunity cost.
Opportunity cost.
And as we are about to see,
we think about the opportunity cost
of holding the money as its cost
in the money market.
So let me draw some axes here,
to start thinking about this money market.
Alright?
So let's call this vertical axis
the nominal interest rate.
Nominal interest rate.
Sometimes you'll see NIR, it's abbreviated.
But we'll just write it out,
the nominal interest rate in that axis.
And the reason I'm focusing on the nominal interest rate
is, we don't know, in this situation,
what inflation is.
We don't know how to calculate the real interest rate
in this situation,
and that's what people look at
when they're making these decisions.
People aren't constantly calculating the real interest rate
because they know exactly what inflation is
in exactly that moment.
They can just see,
'Hey, I could either keep this hundred dollars in my pocket,
'or I could lend it to the government
'and a month later get 101 dollars.'
So we're gonna have the nominal interest rate
on this axis, right over here.
And then in the horizontal axis,
I am going to have the quantity of money.
Quantity of money.
And there is multiple ways
of thinking about which measure of money supply,
and we're gonna think about that in future videos,
but we'll get to that in a second.
The first thing I wanna do
is construct a demand curve for money.
So let me ask you a question.
If nominal interest rates are really high,
so instead of getting 101 dollars back after a month,
if you were to get, I'll say something extreme,
if you were to get 200 dollars back in a month,
would you want to keep a lot of money?
Or would you say,
'Hey, no, I would rather lend that money to the government.'
Well, yes, common sense would tell you,
is if the nominal interest rate is quite high,
then people will perhaps choose to forego holding the money,
and so the quantity of money might be lower.
So we might be in a situation like this.
High nominal interest rate,
hey, that's a high-opportunity cost from holding this cash.
I might wanna lend it to the government,
or to somebody else.
Now, what if the nominal interest rate were really low.
Let's say the government says,
'Hey, you let me borrow a hundred dollars right now,
'in a month I will give you a hundred dollars
'and a tenth of a penny.'
Well then you're like,
'Gee, that doesn't make a lot of sense.
'I would really like to keep my hundred dollars.
'I might need it,
'I might need to do some transactions with it,
'I might want it to be around
'in case the ATM system goes out, whatever.
'You know, there's a hurricane, whatever it might be.'
And so at a low nominal interest rate,
it makes sense that people would wanna hold,
or more likely to hold their cash.
And so you would have higher quantity of money.
And so that explains why economists assume,
often abbreviated as MD,
so this is the demand curve for money,
is downward sloping.
And if we wanted to get a little bit more technical,
some terms that you might see in an economics class,
the famous economist John Maynard Keynes
came up with three particular motives
for this downward-sloping curve,
some of which I've already talked about.
The first he calls the transactions motive.
Transactions.
And that's the idea that one of the primary reasons
you would wanna keep cash is,
well, you might need to use it
if you wanna go buy a candy bar,
or a buy a pet iguana,
that you want that money around.
If you have it lent to the government
and then all of a sudden you see your dream iguana,
then you have to wait a month in order to do it.
So that would be your transactions motive.
A reason, a motivation to hold money.
But once again, the reason why we have
this downward-sloping curve is,
if nominal interest rates are really high,
if the government is willing to pay you
a lot back in a month, then you might say,
'You know what, I'm willing to take the risk.
'Even if I see that dream iguana,
'if I lend the money to the government now,
'in a month, I might be able to buy two iguanas,
'even if they aren't quite my dream iguana.'
And likewise, if nominal interest rates go really down,
you could say, 'Well you know what,
'it's not worth it for me to risk
'not being able to buy that perfect iguana when it shows up,
'so I'm not going to lend it to the government.'
And so the overall quantity of money,
more people are going to keep cash in their pockets.
Now another motive that Keynes talks about
is the precautionary motive.
And this is the idea
that you might wanna just keep cash around
in case there's an emergency.
Let's say the lights go out, there's an earthquake,
there's a hurricane, the ATM system goes out.
Maybe there's a banking holiday for some reason,
and you're going to need some of that cash for transactions.
But once again, it's more precautionary
for that rainy day.
For that bad situation.
And once again, if nominal interest rates are high,
then you might say, 'Well yeah,
'I wanna be cautious but boy,
'I could get a lot back if I lend that money.'
But if your nominal interest rates are low,
you're like, 'You know, it's not worth it,
'I'd rather keep some more money.'
And a lot of people do this,
and so that's why, in general, in that economy,
you're going to have a high quantity of money.
Now the last motive that Keynes talked about
is the speculative motive.
And speculation in general is this idea
of buying something, or selling something,
or waiting to buy something
based on some speculation you have
about whether the price will go up or down.
And so, for example,
you might say, 'Hey, if I wait a couple of days,
'or if I might wait a week,
'the government might give me an even better deal.
'So let me hold onto this.'
And in aggregate, when interest rates are high,
nominal interest rates are high,
people might be willing to forego the ability to speculate.
And when interest rates are low,
they might say, 'You know what,
'I'm just gonna keep my cash for now,
'because there's not a lot to be gained
'by lending that money.'