Fannie Mae and Freddie Mac’s portfolio of subprime loans “performed significantly better” than those packaged into mortgage-backed securities by private issuers, the Financial Crisis Inquiry Commission found in a report. The panel’s report, scheduled to be published tomorrow, attempts to refute claims by Republican lawmakers and some economists that the two government-sponsored enterprises were a driving force behind the growth in subprime home lending that led to the 2008 financial crisis.