Questions: Zero Lower Bound and Monetary Policy Constraints

Question 1

During a severe recession, the central bank has cut the nominal interest rate to zero but the Taylor rule prescribes a rate of −3%. GDP growth remains weak. Which tool can provide additional monetary stimulus?

• A. Cut the federal funds rate a further 3 percentage points into strongly negative territory
• B. Use forward guidance to credibly commit to keeping rates near zero for an extended period and allowing above-target inflation, reducing expected real rates
• C. Raise the inflation target immediately so that the real rate rises and incentivizes saving
• D. Increase reserve requirements to compel banks to lend out excess reserves

Answer: (B)

At the ZLB, conventional rate cuts are exhausted. Forward guidance operates on the Fisher relation: real rate ≈ nominal rate − expected inflation. If the central bank credibly commits to allowing higher future inflation, expected real rates fall even with the nominal rate stuck at zero, stimulating borrowing and spending today. Option A is wrong in practice: cash provides a zero-return alternative, so aggressively negative nominal rates cause cash hoarding. Options C and D are either counterproductive or irrelevant to ZLB stimulus.

Question 2

At the zero lower bound, government fiscal stimulus tends to be more effective than in normal times. What is the primary reason?

• A. The government can borrow at near-zero interest rates, reducing the cost of stimulus programs
• B. The central bank cannot raise interest rates to offset the stimulus, so the usual crowding-out of private investment is muted
• C. Unemployment is automatically higher at the ZLB, which mechanically doubles the fiscal multiplier
• D. Fiscal policy takes over the central bank's role entirely, so its multiplier equals the inverse of the tax rate

Answer: (B)

In normal times, an expansionary fiscal policy causes the central bank to raise interest rates (to prevent overheating), which crowds out private investment and partially offsets the stimulus. At the ZLB, the central bank is already at its floor and cannot (or will not) tighten — so the crowding-out channel is inoperative. The full multiplier effect of government spending passes through to aggregate demand. This is one of the key ways ZLB episodes change macroeconomic policy analysis.

Question 3

The zero lower bound exists because holding physical cash provides a zero nominal return, making it irrational for most agents to deposit money at significantly negative nominal interest rates.

• T. True
• F. False

Answer: True

Cash is the outside option that creates the lower bound. If a bank charges depositors a meaningfully negative rate, rational depositors will withdraw cash and hold it — earning exactly zero — rather than pay to store money in the bank. This flight to cash limits how negative rates can go. Some countries have experimented with mildly negative rates, exploiting the fact that storing large quantities of physical cash has its own costs (security, logistics), but there is a practical floor well above large negative values.

Question 4

At the zero lower bound, a central bank can usually restore economic stimulus by expanding the money supply through standard open-market operations.

• T. True
• F. False

Answer: False

This describes the liquidity trap. At zero interest rates, short-term government bonds and money become near-perfect substitutes — both yield essentially nothing. When the central bank buys short-term bonds and injects reserves, banks and investors simply hold the extra reserves (or swap one zero-yielding asset for another), with no effect on interest rates, lending, or spending. Standard open-market operations lose traction precisely because the substitutability between money and bonds eliminates the interest-rate transmission channel.

Question 5

Explain how forward guidance can lower real interest rates even when the nominal rate is stuck at zero, and why the credibility of the central bank's commitment is critical to this mechanism.

Model answer: The real interest rate equals the nominal rate minus expected inflation. At the ZLB the nominal rate is fixed at approximately zero, so the only way to reduce the real rate is to raise inflation expectations. Forward guidance works by convincing households and firms that the central bank will keep rates at zero for longer than they expected — and will allow inflation to run above target — which raises expected inflation and thus lowers the real rate faced by borrowers today. Credibility is essential: if agents believe the central bank will tighten as soon as inflation picks up (i.e., that the 'commitment' is not genuine), inflation expectations do not move and the real rate stays high. The central bank must credibly promise to be 'irresponsible' — to tolerate future inflation — for the mechanism to work.

This highlights why ZLB policy is fundamentally an expectations management problem. Discretionary monetary policy, which agents know can be reversed, struggles to move long-run inflation expectations. Institutional commitments, price-level targeting, or average inflation targeting frameworks are designed to make such promises more credible.