I really dislike QE because I have theories about how it actually does work. I think the main channel through which QE has effects is via asset prices. To the degree that QE is taken as a signal of central banks “ease”, it communicates information about the course of future interest rates (especially when paired with “forward guidance”). Prolonging expectations of near-zero short rates reduces the discount rate and increases the value of longer duration assets. This “discount rate” effect is augmented by a portfolio balance effect, where private sector agents reluctant (perhaps by institutional mandate) to hold much cash bid up the prices of the assets they prefer to hold (often equities and riskier debt). Finally, there is a momentum effect. To the degree that QE succeeds at supporting and increasing asset prices, it creates a history that gets incorporated into future behavior. Hyperrationally, modern-portfolio-theory estimates of optimal asset-class weights come to reflect the good experience. Humanly, momentum assets quickly become conventional to hold, andmanagers who fail to bow to that lose prestige, clients, even careers. So QE is good for asset prices, particularly financial assets and houses, and rising asset prices can be stimulative of the economy via “wealth effects”. As assetholders get richer on paper, they spend more money, contributing to aggregate demand. As debtors become less underwater, they become less thrifty and prone to deleveraging. Financial asset prices are also the inverse of long-term interest rates, so high asset prices can contribute to demand by reducing “hurdle rates” for borrowing and investing. Lower long term interest rates also reduce interest costs to existing borrowers (who refinance) or people who would have borrowed anyway, enabling them spend on other things rather than make payments to people who mostly save their marginal dollar. Whether the channel is wealth effects, cheaper funds for new investment or consumption, or cost relief to existing debtors, QE only works if it makes asset prices rise, and it is only conducted while it makes those prices rise in real and not just nominal terms.
I think that the asset prices the Fed was targeting was residential housing. A price correction that wiped out the gains from the bubble would have left many bank insolvent and greatly exacerbated the crisis. So the purpose of QE was to prevent liquidation. This had the collateral effect of driving the price of risky assets such as equities higher than they would have been otherwise, adding to the wealth effect. However, I think that supporting housing price was the real aim of the program rather than a broader wealth effect, which the Fed did not mind since it would likely add to spending as a counter to deleveraging.
Interfluidity
Some thoughts on QESteve Randy Waldman
