It’s one of the biggest misconceptions about the housing crisis: the belief that the government’s policies to promote affordable housing — particularly through Fannie Mae and Freddie Mac — fanned the flames of the subprime mortgage market, ultimately bringing down the entire economy.

(Joshua Roberts/Bloomberg)

Over the past few decades, the federal government has tried to promote affordable housing in two major ways. First, the Community Reinvestment Act encouraged banks to lend to low-income communities. Second, Congress mandated that Fannie and Freddie hit certain targets for lending to low-income and minority communities.

Researchers from the St. Louis Fed analyzed whether such policies “influenced origination or affected prices of subprime mortgages.” While they confirmed that Fannie and Freddie did make widespread purchases of risky, mortgage-backed securities, they conclude that such moves were not, in fact, the result of these affordable housing mandate.

“Affordable housing goals may have introduced some distortions and created perverse incentives in the mortgage market but these were not the driving force behind the tremendous growth of subprime and Alt-A loans in the private market,” explains Cristian deRitis, a director at Moody’s Analytics. Fannie and Freddie pursued what turned out to be the riskiest loans not to meet the affordable housing mandate, but instead “to increase profit,” as they were assumed to be higher yield, deRitis tells me.

My colleague Brad looked at some of the previous research on this, explaining why Barney Frank — a big proponent of Fannie and Freddie’s affordable housing mandate — isn’t to blame for the housing crisis, either.