Questions: Quantitative Easing and Unconventional Monetary Policy

Question 1

Suppose bonds and bank reserves are perfect substitutes — investors are completely indifferent between holding them. A central bank conducts a large QE program, buying $500 billion in long-term bonds. What happens to long-term interest rates?

• A. Long-term rates fall substantially because the central bank has injected money into the economy
• B. Long-term rates fall moderately through the signaling channel even if portfolio effects are zero
• C. Long-term rates are unchanged — if bonds and reserves are perfect substitutes, the asset swap is neutral
• D. Long-term rates rise because the central bank has crowded out private investors

Answer: (C)

This is the irrelevance result: QE works through frictions, and if bonds and reserves are perfect substitutes, there is no friction for QE to exploit. Investors simply swap one safe asset for another, with no incentive to shift into riskier assets (no portfolio balance effect). The swap is financially neutral. This is why QE's effectiveness is fundamentally a question about market structure — it depends on imperfect substitutability. Options A and B reflect transmission channels that require frictions to operate. Option D is incorrect; in this frictionless world, no crowding occurs because the swap is neutral.

Question 2

A financial crisis causes the mortgage-backed securities market to freeze — no buyers, no pricing, lending has stopped. The central bank begins purchasing MBS at scale. Which QE transmission channel is primarily at work?

• A. The portfolio balance channel — removing MBS from markets forces investors into equities
• B. The signaling channel — purchasing MBS signals future low interest rates
• C. The credit channel — directly restoring market liquidity enables lending to resume
• D. The fiscal channel — the central bank's purchases function as government stimulus spending

Answer: (C)

The credit channel operates precisely when specific markets seize up during financial crises. By purchasing distressed MBS, the central bank acts as a buyer of last resort, restoring pricing and liquidity in those markets so that lending can resume. This is distinct from the portfolio balance channel (which relies on investors rebalancing into other assets) and the signaling channel (which works through forward interest rate expectations). The fiscal channel is not a QE transmission channel — QE is a central bank operation, not government spending.

Question 3

QE is sometimes described as 'money printing' because the central bank creates new reserves to purchase bonds. This framing correctly describes how QE injects stimulus into the real economy.

• T. True
• F. False

Answer: False

While QE does involve creating new electronic reserves, calling it 'money printing' in the distributional sense is misleading. QE is an asset swap: the central bank exchanges reserves (a liability it creates) for bonds (an asset it acquires). The public does not receive cash — bond sellers receive reserves credited to their bank accounts at the central bank. This is fundamentally different from helicopter money (direct transfers to households) or deficit-financed government spending. QE stimulates the economy only to the extent that the asset swap affects financial conditions through imperfect substitutability — the transmission is indirect and friction-dependent, not mechanical.

Question 4

The effectiveness of QE is primarily a question about the structure of financial markets rather than about the quantity of assets purchased.

• T. True
• F. False

Answer: True

QE's impact hinges entirely on whether bonds and reserves are imperfect substitutes. If markets are segmented (investors have preferred habitats), removing bond supply forces them to rebalance, lowering long-term yields. If they are nearly perfect substitutes, even large purchases have minimal effect. This explains why the same nominal volume of QE can have very different effects across countries and time periods — the relevant variable is the degree of market segmentation, not simply the dollar amount. Empirically, the debate over QE's real effects reflects genuine uncertainty about the degree of substitutability in different financial market contexts.

Question 5

Explain why QE's effectiveness depends on whether long-term bonds and short-term reserves are good substitutes, and what the portfolio balance channel claims about this relationship.

Model answer: If bonds and reserves are perfect substitutes, investors are indifferent between holding them, so swapping one for the other changes nothing — the irrelevance result. The portfolio balance channel claims they are NOT perfect substitutes: investors have preferred habitats (regulatory requirements, liability matching, risk preferences) that make them reluctant to hold more reserves and fewer bonds than they would choose. When QE removes bonds from markets, investors seeking duration must bid up prices on remaining assets, pushing long-term yields down and stimulating investment and consumption. The channel's strength is therefore determined by the degree of market segmentation — strong segmentation means powerful QE; weak segmentation means largely irrelevant QE.

This is the core conceptual insight: QE is not mechanically powerful. It requires market frictions to work. The portfolio balance channel is the primary theory of why QE lowers long-term rates, and its empirical magnitude is directly tied to how imperfectly substitutable bonds and reserves actually are in practice. Countries with more segmented financial markets (institutional investors with strict duration requirements) tend to see larger QE effects than those with more flexible investors.