by Calculated Risk on 8/20/2012 07:34:00 PM

Fed Working Paper by Paolo Gelain, Norges Bank, Kevin Lansing, Federal Reserve Bank of San Francisco and Norges Bank, and Caterina Mendicino, Bank of Portugal: House Prices, Credit Growth, and Excess Volatility: Implications for Monetary and Macroprudential Policy

The researchers looked at the house bubble and several possible policy responses. It appears the most effective policy - for limiting the bubble - would have been to require lenders to focus more on loan-to-income.

From the paper:

Our final policy experiment achieves a countercyclical loan-to-value ratio in a novel way by requiring lenders to place a substantial weight on the borrower’s wage income in the borrowing constraint. As the weight on the borrower’s wage income increases, the generalized borrowing constraint takes on more of the characteristics of a loan-to-income constraint. Intuitively, a loan-to-income constraint represents a more prudent lending criterion than a loan-to-value constraint because income, unlike asset value, is less subject to distortions from bubble-like movements in asset prices. Figure 4 [see below] shows that during the U.S. housing boom of the mid-2000s, loan-to-value measures did not signal any significant increase in household leverage because the value of housing assets rose together with liabilities. Only after the collapse of house prices did the loan-to-value measures provide an indication of excessive household leverage. But by then, the over-accumulation of household debt had already occurred. By contrast, the ratio of U.S. household debt to disposable personal income started to rise rapidly about five years earlier, providing regulators with a more timely warning of a potentially dangerous buildup of household leverage.

We show that the generalized borrowing constraint serves as an “automatic stabilizer” by inducing an endogenously countercyclical loan-to-value ratio. In our view, it is much easier and more realistic for regulators to simply mandate a substantial emphasis on the borrowers’ wage income in the lending decision than to expect regulators to frequently adjust the maximum loan-to-value ratio in a systematic way over the business cycle or the financial/credit cycle.
...
... the most successful stabilization policy in our model calls for lending behavior that is basically the opposite of what was observed during U.S. housing boom of the mid-2000s. As the boom progressed, U.S. lenders placed less emphasis on the borrower’s wage income and more emphasis on expected future house prices. So-called “no-doc” and “low-doc” loans became increasingly popular. Loans were approved that could only perform if house prices continued to rise, thereby allowing borrowers to refinance. It retrospect, it seems likely that stricter adherence to prudent loan-to-income guidelines would have forestalled much of the housing boom, such that the subsequent reversal and the resulting financial turmoil would have been less severe.

Click on graph for larger image.

From the paper:

Figure 4: During the U.S. housing boom of the mid-2000s, loan-to-value measures did not signal a significant increase in household leverage because the value of housing assets rose together with liabilities. In contrast, the debt-to-income ratio provided a much earlier warning signal of a potentially dangerous buildup of household leverage.

Something to remember when the next lending bubble comes along. Also note that debt-to-income is still very high and there is more deleveraging to come.