There has been no shortage of studies suggesting that Fannie Mae’s and Freddie Mac’s phenomenal growth over the past decade has exposed U.S. taxpayers to more risk. And the Financial Services Roundtable, a trade group representing finance companies and banks, last week added to the supply by releasing its own study, entitled “On Shaky Ground: The Relentless Expansion of Fannie Mae and Freddie Mac in the U.S. Housing Finance System.