As the government-sponsored enterprises slowly wind down their massive domination of the mortgage finance markets, the most likely parties to fill the capital hole left behind are the big four banks. However, how well or how much the big four can cover remain up for discussion. On Tuesday, speakers tossed ideas back and forth at a panel titled: “Housing Finance Reform Proposals.” They gathered in Washington at the annual meeting of the American Securitization Forum, a trade group representing secondary market players. One speaker wryly referred to the unofficial title of the panel as “life without the GSEs.” The future may be murky, and the present is unlikely to change in the near-term, one panelist said. The evolution of the mortgage finance markets away from government support will become clearer as financial reform under Dodd-Frank begins to take hold. Until then, according to Alfred Pollard, general counsel Federal Housing Finance Agency, the government will continue support Fannie Mae, Freddie Mac and the dozen Federal Home Loan Banks. “If the enterprises are in conservatorship we are supposed to conserve their assets,” Pollard said. “We made a decision that Fannie and Freddie, and home loan banks should stick to their core businesses.” Moderator Christopher DiAngelo, partner at Katten Muchin Rosenman, said Bank of America (BAC), Citigroup(C), JPMorgan Chase(JPM) and Wells Fargo(WFC) hold 70% of the private mortgage origination market. Therefore, they seem the likely option to take market share from the GSEs. Others financing options, such as developing a covered bond market or a greater presence of private investor bases, such as from real estate investment trusts, are only going to handle a small portion of the financing, the panel said. “A covered bond market does not solve a lot of problems,” said Nancy Mueller Handal of MetLife Investments, a $45 billion investor in mortgage-backed securities, 80% of which are GSE bonds. “There is not the investor base to fill the gap that people think. We would have very little room for covered bonds,” she added. Furthermore, investors want a stronger foundation for investments in private-label MBS. Those investors will want vertical risk retention, adequate access to representations and warranties and a third-party arbitrator assigned to deals. “The pipes are not in place yet,” Handal added. Write to Jacob Gaffney. Follow him on Twitter @JacobGaffney.