Freedom is nowhere near the size of behemoths like Citigroup Inc. or Bank of America Corp.; yet last year it originated more mortgages than either of them, some $51.1 billion, according to industry research group Inside Mortgage Finance. It is now the 11th-largest mortgage lender in the U.S., up from No. 78 in 2012. Its rise points to a bigger shift in the home-lending business to specialized mortgage lenders that fall outside the banking sector. Such nonbanks, critically wounded in the housing crisis, have re-emerged to become the market’s dominant players, with 52% of U.S. mortgage originations, up from 9% in 2009. Six of the 10 biggest U.S. mortgage lenders today are nonbanks, according to the research group.