Wait! Government did cause the housing bubble.

Congress's Community Reinvestment Act, aimed at helping the poor afford housing, did lead banks to make much riskier mortgage loans, a new study finds. 

Austrian business cycle theory explains the general pattern of the boom-bust cycle — credit expansion, lowered interest rates, malinvestment, crash, liquidation — but the particulars differ in each historical case. (Austrians sometimes distinguish “typical” from “unique” features of each cycle.) To explain particular episodes, we appeal to specific technological, regulatory, political, legal, or other conditions. For example, in the 1990s, much of the malinvestment was channeled into the IT sector, where uncertainty driven by rapid technological change made entrepreneurs particularly susceptible to forecasting errors. In the 2000s, of course, malinvestment appeared largely in real estate, the result of government programs designed to relax underwriting standards and otherwise increase investment in particularly risky real-estate assets. In other words, ABCT tells us to look for malinvestment during the boom, but not where that malinvestment will show up.

Regarding the latter example, however, there has been a persistent dispute among mainstream economists about the role of government housing policy, particularly the Community Reinvestment Act which was used, in the 1990s, to make banks increase their lending to particular low-income neighborhoods. Paul Krugman asserts, for example, that the “Community Reinvestment Act of 1977 was irrelevant to the subprime boom.” Actually, no. A new NBER paper (gated) on the CRA is causing quite a stir. Authored by four economists from NYU, MIT, Northwestern, and Chicago, the paper is the first to use instrumental-variables regression to distinguish changes in bank lending caused by the CRA from changes that would likely have happened anyway. (The authors use the timing of loan decisions relative to the dates of CRA audits to identify the effect of the CRA on lending.) The results suggest that CRA enforcement did, contra Krugman, lead banks to make substantially riskier loans than otherwise. Raghu Rajan puts it in a very Austrian-sounding way:

The key then to understanding the recent crisis is to see why markets offered inordinate rewards for poor and risky decisions. Irrational exuberance played a part, but perhaps more important were the political forces distorting the markets. The tsunami of money directed by a US Congress, worried about growing income inequality, towards expanding low income housing, joined with the flood of foreign capital inflows to remove any discipline on home loans. And the willingness of the Fed to stay on hold until jobs came back, and indeed to infuse plentiful liquidity if ever the system got into trouble, eliminated any perceived cost to having an illiquid balance sheet.

I’d reverse the order of emphasis — credit expansion first, housing policy second — but Rajan is right that government intervention gets the blame all around.