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Mortgage-backed securities I | Finance & Capital Markets | Khan Academy - YouTube
Channel: Khan Academy
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Welcome to my presentation on
mortgage-backed securities.
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Let's get started.
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And this is going to be part
of a whole new series of
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presentations, because I think
what's happening right now in
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the credit markets is pretty
significant from, I guess, a
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personal finance point of
view and just from a
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historic point of view.
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And I want to do a whole set
of videos just so people
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understand, I guess, how
everything fits together, and
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what the possible repercussions
could be.
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But we have to start
with the basics.
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So what is a mortgage-backed
security?
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You've probably read
a lot about these.
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So historically, let's think
about what historically
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happens when I went to get a
loan for a house, let's say,
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20 years ago.
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And I'm going to simplify
some things.
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And later we can do
a more nuanced.
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Where'd my pen go?
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Let's say I need $100,000.
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No, let me say $1 million,
because that's actually closer
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to how much houses cost now.
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Let's say I need a $1 million
loan to buy a house, right?
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This is going to be a mortgage
that's going to be
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backed by my house.
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And when I say backed by my
house, or secured by my house,
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that means that I'm going to
borrow $1 million from a bank,
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and if I can't pay back
the loan, then the
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bank gets my house.
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That's all it means.
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And oftentimes it'll only be
secured by the house, which
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means that I could just give
them back the keys.
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They get the house and I have
no other responsibility, but
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of course my credit
gets messed up.
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But I need a $1 million loan.
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The traditional way I got a $1
million loan is I would go and
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talk to the bank.
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This is the bank.
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They have the money.
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And then they would give me $1
million and I would pay them
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some type of interest. I'll
make up a number.
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The interest rates obviously
change, and we'll do future
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presentations on what causes the
interest rates to change.
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But let's say I would pay them
10% interest. And for the sake
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of simplicity, I'm going to
assume that the loans in this
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presentation are interest-only
loans.
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In a traditional mortgage, you
actually, your payment has
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some part interest and
some part principal.
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Principal is actually when
you're paying down the loan.
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The math is a little bit more
difficult with that, so what
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we're going to do in this case
is assume that I only pay the
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interest portion, and at the
end of the loan I pay the
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whole loan amount.
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So let's say that this
is a 10-year loan.
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So for each year of the 10
years, I'm going to pay
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$100,000 in interest. $100,000
per year, right?
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And then in year 10, I'm going
to pay the $100,000 and I'm
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also going to pay back
the $1 million.
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Right?
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Year 1, 2, 3, dot, dot,
dot, dot, 9, 10.
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So in year one, I
pay $100,000.
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Year two, I pay $100,000.
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Year three, I pay $100,000.
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Dot, dot, dot, dot.
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Year nine, I pay $100,000.
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And then year 10, I pay the
$100,000 plus I pay back the
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$1 million.
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So I pay back $1.1 million.
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So that's kind of how the cash
is going to be transferred
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between me and the bank.
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And this is how a-- I don't
want to say a traditional
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loan, because this isn't
a traditional loan, an
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interest-only loan-- but for the
sake of this presentation,
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how it's different than a
mortgage-backed security, the
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important thing to realize
is that the bank would
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have kept the loan.
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These payments I would have been
making would have been
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directly to the bank.
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And that's what the
business that,
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historically, banks were in.
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Another person, you-- and you
have a hat-- let's say you're
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extremely wealthy and
you would put $1
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million into the bank.
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Right?
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That's just your life savings
or you inherited
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it from your uncle.
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And the bank would pay you,
I don't know, 5%.
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And then take that $1 million,
give it to me, and get 10% on
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what I just borrowed.
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And then the bank makes
the difference, right?
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It's paying you 5% percent and
then it's getting 10% from me.
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And we can go later into how
they can pull this off, like
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what happens when you have
to withdraw the money,
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et cetera, et cetera.
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But the important thing to
realize is that these payments
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I make are to the bank.
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That's how loans worked before
the mortgage-backed security
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industry really got developed.
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Now let's do the example with
a mortgage-backed security.
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Now there's still me.
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I still exist. And I still
need $1 million.
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Let's say I still
go to the bank.
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Let's say I go to the bank.
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The bank is still there.
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And like before, the bank
gives me $1 million.
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And then I give the
bank 10% per year.
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Right?
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So it looks very similar
to our old model.
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But in the old model,
the bank would keep
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these payments itself.
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And that $1 million it had is
now used to pay for my house.
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Then there was an innovation.
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Instead of having to get more
deposits in order to keep
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giving out loans, the bank said,
well, why don't I sell
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these loans to a third
party and let them do
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something with it?
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And I know that that might
be a little confusing.
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How do you sell a loan?
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Well let's say there's me.
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And let's say there's
a thousand of me.
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Right?
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There's a bunch of Sals
in the world.
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Right?
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And we each are borrowing
money from the bank.
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So there's a thousand of me.
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Right?
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I'm just saying any kind
of large number.
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It doesn't have to
be a thousand.
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And collectively we
have borrowed a
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thousand times a million.
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So we've collectively borrowed
$1 billion from the bank.
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And we are collectively paying
10% on that, right?
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Because each of us are going to
pay 10% per year, so we're
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each going to pay 10%
on that $1 billion.
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Right?
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So 10% on that $1 billion is
$100 million in interest. So
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this 10% equals $100 million.
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Now the bank says, OK, all the
$1 billion that I had in my
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vaults, or whatever-- I guess
now there's no physical money,
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but in my databases-- is now
out in people's pockets.
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I want to get more money.
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So what the bank does is it
takes all these loans
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together, that $1 billion in
loans, and it says, hey,
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investment bank-- so that's
another bank-- why don't you
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give me $1 billion?
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So the investment bank gives
them $1 billion.
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And then instead of me and the
other thousands of me paying
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the money to this bank, we're
now paying it to this new
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party, right?
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I'm making my picture
very confusing.
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So what just happened?
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When this bank sold the loans--
grouped all of the
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loans together and it folded it
into a big, kind of did it
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on a wholesale basis--
it's sold a thousand
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loans to this bank.
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So this bank paid $1 billion
for the right to get the
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interest and principal payment
on those loans.
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So all that happened is, this
guy got the cash and then this
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bank will now get the
set of payments.
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So you might wonder, why
did this bank do it?
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Well I kind of glazed over the
details, but he probably got a
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lot of fees for doing this, or
maybe he just likes giving
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loans to his customers,
whatever.
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But the actual right answer
is that he got
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fees for doing this.
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And he's actually probably going
to transfer a little bit
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less value to this guy.
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Now, hopefully you understand
the notion of actually
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transferring the loan.
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This guy pays money and now the
payments are essentially
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going to be funnelled to him.
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I only have two minutes left
in this presentation, so in
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the next presentation I'm going
to focus on what this
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guy can now do with the
loan to turn it into a
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mortgage-backed security.
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And this guy's an investment
bank instead of
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a commercial bank.
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That detail is not that
important in understanding
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what a mortgage-backed security
is, but that will
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have to wait until the
next presentation.
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See you soon.
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