Home prices are improving at a rapid pace throughout the nation, sparking bidding wars in certain markets, according to several different indices. But this rise in “home equity” is also spurring talk that the two largest players in residential finance – Fannie Mae and Freddie Mac – could be sitting on large unrealized gains in both their MBS and whole loan portfolios. One veteran MBS investor told Inside MBS & ABS that home values have improved so much over the past 120 days that the government-sponsored enterprises may be looking at “monster” increases in the value of their holdings. “Keep in mind that these two are sitting on loans where a year ago the loan-to-value ratio was 115 percent,” said this investor. “But most of this stuff isn’t underwater anymore. If [the GSEs] re-calculate their reserves, they will see some huge gains.” In its 10-Q filing for the first quarter, Fannie reported...