Senate negotiators working on the financial-regulatory bill today rejected a proposal from House Republicans that would make big banks liable for the costs of winding down Fannie Mae and Freddie Mac. The proposal would have made the government-controlled home loan companies, which own or guarantee more than half of the $11trn US mortgage market, part of a Wall Street-financed “rainy day” fund that would be used to pay for the liquidation of large failed companies.