NOT ALL BUBBLES PRESENT A RISK TO THE ECONOMY / THE FINANCIAL TIMES COMMENTARY & ANALYSIS ( HIGHLY RECOMMENDED READING )

Not all bubbles present a risk to the economy

By Frederic Mishkin

Published: November 9 2009 20:08

There is increasing concern that we may be experiencing another round of asset-price bubbles that could pose great danger to the economy. Does this danger provide a case for the US Federal Reserve to exit from its zero-interest-rate policy sooner rather than later, as many commentators have suggested? The answer is no.

Are potential asset-price bubbles always dangerous? Asset-price bubbles can be separated into two categories. The first and dangerous category is one I call “a credit boom bubble”, in which exuberant expectations about economic prospects or structural changes in financial markets lead to a credit boom. The resulting increased demand for some assets raises their price and, in turn, encourages further lending against these assets, increasing demand, and hence their prices, even more, creating a positive feedback loop. This feedback loop involves increasing leverage, further easing of credit standards, then even higher leverage, and the cycle continues.

Eventually, the bubble bursts and asset prices collapse, leading to a reversal of the feedback loop. Loans go sour, the deleveraging begins, demand for the assets declines further and prices drop even more. The resulting loan losses and declines in asset prices erode the balance sheets at financial institutions, further diminishing credit and investment across a broad range of assets. The resulting deleveraging depresses business and household spending, which weakens economic activity and increases macroeconomic risk in credit markets. Indeed, this is what the recent crisis has been all about.

The second category of bubble, what I call the “pure irrational exuberance bubble”, is far less dangerous because it does not involve the cycle of leveraging against higher asset values. Without a credit boom, the bursting of the bubble does not cause the financial system to seize up and so does much less damage. For example, the bubble in technology stocks in the late 1990s was not fuelled by a feedback loop between bank lending and rising equity values; indeed, the bursting of the tech-stock bubble was not accompanied by a marked deterioration in bank balance sheets. This is one of the key reasons that the bursting of the bubble was followed by a relatively mild recession. Similarly, the bubble that burst in the stock market in 1987 did not put the financial system under great stress and the economy fared well in its aftermath.

Because the second category of bubble does not present the same dangers to the economy as a credit boom bubble, the case for tightening monetary policy to restrain a pure irrational exuberance bubble is much weaker. Asset-price bubbles of this type are hard to identify: after the fact is easy, but beforehand is not. (If policymakers were that smart, why aren’t they rich?) Tightening monetary policy to restrain a bubble that does not materialise will lead to much weaker economic growth than is warranted. Monetary policymakers, just like doctors, need to take a Hippocratic Oath to “do no harm”.

Nonetheless, if a bubble poses a sufficient danger to the economy as credit boom bubbles do, there might be a case for monetary policy to step in. However, there are also strong arguments against doing so, which is why there are active debates in academia and central banks about whether monetary policy should be used to restrain asset-price bubbles.

But if bubbles are a possibility now, does it look like they are of the dangerous, credit boom variety? At least in the US and Europe, the answer is clearly no. Our problem is not a credit boom, but that the deleveraging process has not fully ended. Credit markets are still tight and are presenting a serious drag on the economy.

Tightening monetary policy in the US or Europe to restrain a possible bubble makes no sense at the current juncture. The Fed decision to retain the language that the funds rate will be kept “exceptionally low” for an “extended period” makes sense given the tentativeness of the recovery, the enormous slack in the economy, current low inflation rates and stable inflation expectations. At this critical juncture, the Fed must not take its eye off the ball by focusing on possible asset-price bubbles that are not of the dangerous, credit boom variety.

The writer is a professor of finance and economics at the graduate school of business, Columbia University, a former member (governor) of the Fed board of governors and author of The Economics of Money, Banking, and Financial Markets, 9th edition (2009)


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