Despite signing a major regulatory settlement and struggling to cope with a massive accounting and management overhaul, Fannie Mae this year appears to be regaining some market share from its rival government-sponsored enterprise. With monthly business summaries now updated through May, Fannie’s production of new MBS has jumped 11.2 percent from the same period in 2005. Over the same period, Freddie’s issuance of new mortgage securities is up just 2.0 percent. That trend held… [One data tables included]