Transcript File
The Stock Market and the Economy
Introduction to Economics
Johnstown High School
Mr. Cox
How the Stock Market Affects the
Economy
On October 19, 1987, there was a dramatic drop in the stock market
One that made declines in 2001 and 2008 seem small by comparison
Dow Jones Industrial Average fell by 508 points—a drop of 23%— about $500
billion in household wealth disappeared
Newscaster Sam Donaldson asked, “Mr. President, are you concerned about the
drop in the Dow?”
As Reagan entered his helicopter, he smiled calmly and replied,
“Why, no, Sam. I don’t own any stocks”
It was a curious exchange (perhaps Reagan was joking)
Whatever Reagan’s intent, statement was startling
Because, in fact, stock market does matter to all Americans
The Wealth Effect
To understand how market affects economy, let’s run through following
mental experiment
Suppose that, for some reason stock prices rise
When stock prices rise, so does household wealth
What do households do when their wealth increases?
Typically, they increase their spending
Link between stock prices and consumer spending is an important one, so
economists have given it a name
Wealth effect
Tells us that autonomous consumption spending tends to move in same direction
as stock prices
When stock prices rise (fall), autonomous consumption spending rises (falls)
The Wealth Effect and Equilibrium GDP
Autonomous consumption is a component of total spending
Can summarize logic of the wealth effect
Changes in stock prices—through the wealth
effect—cause both equilibrium GDP and price level
to move in same direction
An increase in stock prices will raise equilibrium GDP and
price level
While a decrease in stock prices will decrease both equilibrium
GDP and price level
The Wealth Effect and Equilibrium GDP
How important is wealth effect?
Economic research shows that marginal propensity to consume out of wealth
is between 0.03 and 0.05
Change in consumption spending for each one-dollar rise in wealth
As a rule of thumb, a 100-point rise in DJIA—which generally means a rise
in stock prices in general—causes household wealth to rise by about $100
billion
This rise in household wealth will increase autonomous consumption
spending by between $3 billion and $5 billion—we’ll say $4 billion
Rapid increases in stock prices can cause significant positive demand shocks
to economy, shocks that policy makers cannot ignore
Similarly, rapid decreases in stock prices can cause significant negative
demand shocks to economy, which would be a major concern for policy
makers
Figure 4: The Effect of Higher Stock
Prices on the Economy
Aggregate Expenditure
(a)
(b)
AS
Price
Level
AEhigher stock prices
AElower stock prices
P2
P1
ADhigher stock prices
ADlower stock prices
45°
Y1
Y2
Real GDP
Y1 Y3 Y2
Real GDP
How the Economy Affects the Stock Market
Let’s look at the other side of the two-way relationship
How economy affects stock prices
Many different types of changes in the overall economy can affect the
stock market
Let’s start by looking at the typical expansion
Real GDP rises rapidly over several years
In typical expansion (recession), higher (lower) profits and stockholder
optimism (pessimism) cause stock prices to rise (fall)
What Happens When Things Change?
Figure 5 illustrates three different types of changes we might
explore
A change might have most of its initial impact on the overall
economy, rather than the stock market
There might be a shock that initially affects stock market
Shock could have powerful, initial impacts on both stock market
and overall economy
Figure 5: Three Types of Shocks
Shock to
stock market
Shock to
macroeconomy
Stock Market
Macroeconomy
Shock to both
stock market and
macroeconomy
A Shock to the Economy
Imagine that new legislation greatly increases government purchases
To equip public schools with more sophisticated telecommunications
equipment, or to increase the strength of our armed forces
What will happen?
Rise in government purchases will first increase real GDP through expenditure
multiplier
When we include effects of stock market, expenditure multiplier is larger
An increase in spending that increases real GDP will also cause stock prices
to rise, causing still greater increases in real GDP
Similarly, a decrease in spending that causes real GDP to fall will also cause
stock prices to fall, causing still greater decreases in real GDP
This is one reason why stock prices are so carefully watched by policy makers, and
matter for everyone
Whether they own stocks themselves or not
The Fed and the Stock Market
Experience of late 1990s and early 2000s raised some
important questions about relationship between Federal
Reserve and stock market
In 1995 and 1996, Greenspan and other Fed officials began to
worry that share prices were rising out of proportion to the
future profits they would be able to deliver to their owners
In this view, market in late 1990s resembled stock market in
1920s, which is also often considered a bubble
The Fed and the Stock Market
In 1996, when Alan Greenspan first made his “irrational exuberance” speech, he
seemed to side with those who believed that the stock market was in midst of a
speculative bubble
Fed would be forced to intervene to prevent wealth effect—this time in a negative
direction—from creating a recession
Could Fed do so?
Probably
In mid-1990s, Greenspan seemed to be trying to “talk the market down” by
letting stockholders know that he thought share prices were too high
Implied threat
If stocks rose any higher, Fed would raise interest rates and bring them down
It didn’t work