Chart 1 illustrates how the growing proportion of nonprime first mortgage loans helped fuel the sharp rise in home prices. As home prices rose and the stock market performed strongly, household net worth rose sharply. Households responded by borrowing more and saving less. After all, why save when the rise in home prices was adding to your wealth and the housing equity created by the rise in home prices could be easily tapped for funds as needed? The use of home equity as a source for funds to support consumption is evident in the fact that the homeowners’ equity as a share of home values was essentially flat over this period (Chart 2). This indicates that homeowners were borrowing against their accumulated gains. The surge in home prices pushed up the ratio of household net worth to disposable income to nearly 640 percent and the personal saving fell below 2 percent (Chart 3). The surge in home prices was fueled by products and practices in the financial sector that led to a rapid and unsustainable buildup of leverage and an underpricing of risk during this period. These dynamics in turn provided the fuel that caused house prices and consumer spending to rise much faster than income. As shown in Chart 4, the share of GDP accounted for by consumption and residential investment climbed to a peak of 76 percent in 2005 from 71 percent in the mid-1990s. The boom, of course, was unsustainable.
For example, if inflation in 2011 were a 0.5 percentage point below the Fed’s inflation objective, the Fed might aim to offset this miss by an additional 0.5 percentage point rise in the price level in future years. In the current environment, such an approach would have some advantages as well as some disadvantages. When there is a large amount of slack in the economy, the Federal Reserve might not easily be able to hit an inflation objective soon. But, the central bank could plausibly promise to make up the difference later on. Indeed, the further the Fed fell behind its inflation objective in the near term, the more inflation would need to increase in order to  BIS Review 127/2010  5  push the actual path of prices up to the path consistent with price stability over the long run. To the extent this policy was more credible, it might do a better job keeping inflation expectations from falling. This might make monetary policy more stimulative and, thus, might help the FOMC achieve its objectives more quickly. However, such an approach would only work well if people understood how it would operate and formed their expectations of future inflation accordingly. And there could also be significant costs. For example, if people mistakenly concluded that the Fed was tinkering with its long-run inflation objective, this could lead to greater uncertainty about future inflation.