2008 Crisis & Short Run Model

Chapter 14 – 2008 Crisis and the Short-Run Model.

Problem 1 – A Financial Crisis

Suppose the economy starts with GDP at potential, the real interest rate and the marginal product of capital both equal to 3 percent, and a stable inflation rate of 2 percent. A mild financial crisis hits that raises the risk premium from zero to 2 percent.


(a) Analyze the effect of this shock in the IS/MP diagram. 


In Equilibrium, the IS/MP Diagram looks like,


Risk Premium & Where It May Come From - Recall Problem 4 from the 2008 Crisis Overview Chapter, we discussed systemic risk and how loans between banks could expose creditor banks to risk for which they were otherwise unaware. With the previous chapter’s problem, a debtor bank’s exposure to a dramatic fall in housing prices spread to a creditor bank through interbank loans.


This would presumably imply that when banks loan to each other they would charge a risk premium. This risk premium increases with the chances of a crisis that could harm a debtor bank’s balance sheet. This premium would decrease in times of relative calm.


The real interest rate would therefore take the form;


Where  is the “risk free rate” (think: the rate set by the central bank)

and  is the risk premium


IS-Curve – Normally a “mild financial crisis” will shift the IS curve inward. But because this equation didn’t mention anything about a shift, I’ll assume the IS is unchanged focus on how the new risk premium changes the MP curve.


This shift will push short-run output into recessionary territory.



(b) What policy response would you recommend to the Federal Reserve? What would be the effect of this policy response on the economy?

In this model, the Fed influences the risk free rate . After the jump up on the risk premium from zero to 2%, in order to get the real interest rate back up to the equilibrium of the marginal product of capital of 3%, the Fed would need to offset the risk premium change and lower  by 2%


Before the crisis:

After the risk premium increase:


With Fed response:


This Fed response would look like the following in a IS/MP diagram;



The Fed lowered its interest rate,  to 1%, making the real interest rate 3%, and bringing the economy back to equilibrium with .



(c) How would your answer to part (b) change if the financial crisis were very severe, raising the risk premium to 6 percent? 

With a 6% risk premium, our IS/MP diagram would have looked something like this,



To get the economy back to equilibrium with a 6% risk premium the Fed will want to lower rates by 6%. But when setting the risk free rate , the central bank faces a zero-lower-bound. It can’t set rates below zero. Thus the Fed in this scenario  can only lower rates by 3% (the current risk-free-rate). This means the best response of the central bank to this crisis still leaves the economy in a slumping economy.



(d) What other policy responses might be considered in this case? 


Other options include fiscal expansion. Plus….



Fall 2010 Final 3:

If the risk premium increases the government should lower taxes.

From the chapter on the 2008 Financial Crisis and the Short-Run Model.


In this chapter the regular IS model was changed so that real interest rates are, 

Where R-ff-sub-t is the risk free rate (the ‘ff’ is for ‘federal funds’ rate, set by the Fed).  is set by the Fed. P-bar is the risk premium.


With the risk premium, the idea is that if the Central Bank wants to keep the real interest rate unchanged, it needs to offset any change in the risk premium by a change in the risk-free rate. So if the risk premium goes up, the Fed needs to lower the risk-free rate.


Great, so that doesn’t have anything to do with “the government should lower taxes”. So, in a strong sense the answer is FALSE.


However, suppose the risk premium increases a lot, and is associated with a big inward shift in the IS curve (ala the 2008+ crisis, where the IS curve shifted in with a big recession and the risk premium shot up). If the Fed reaches their ‘zero-lower-bound’ of the risk free rate (can’t be less than 0) and still can’t bring the economy back to equilibrium, then the next option for the government is a fiscal stimulus and/or tax breaks. (The book mentions a few other options too.)

So this could be TRUE too, if you mentioned all that.






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