The Federal Reserve’s Alex Kaufman has posted The Influence of Fannie and Freddie on Mortgage Loan Terms to SSRN.  It is behind a paywall on SSRN, but an earlier draft is available elsewhere on the web. The abstract reads,

This article uses a novel instrumental variables approach to quantify the effect that government‐sponsored enterprise (GSE) purchase eligibility had on equilibrium mortgage loan terms in the period from 2003 to 2007. The technique is designed to eliminate sources of bias that may have affected previous studies. GSE eligibility appears to have lowered interest rates by about ten basis points, encouraged fixed‐rate loans over ARMs and discouraged low documentation and brokered loans. There is no measurable effect on loan performance or on the prevalence of certain types of “exotic” mortgages. The overall picture suggests that GSE purchases had only a modest impact on loan terms during this period.

This is pretty dry reading, but it is actually an important project: “[g]iven the GSEs’ vast scale, the liability they represent to taxpayers, and the decisions that must soon be made about their future, it is crucial to understand how exactly they affect the mortgage markets in which they operate.” (2, earlier draft) The current conventional wisdom is that the two companies will return in something that looks like their pre-conservatorship form.

Given that that is the case, studies such as these are useful for providing some facts about the actual impact that these two companies actually have on the mortgage market.  In terms of their impact on loan terms, it appears that the two companies have a modest or even “mixed” effect, at least for the subset of mortgages studied. (22, earlier draft) And there “is no measurable effect on loan performance” at all. (22, earlier draft)

I have argued previously that returning Fannie and Freddie to their pre-conservatorship ways is a bad call. I still think that is the case. And I think studies such as these offer support for that view, in the face of the conventional wisdom.