Fannie Mae, Freddie Mac touch off swaps scrap

The regulator of Fannie Mae and Freddie Mac is on the cusp of making big changes to the market for interest-rate swaps, in a move that could potentially cut into Wall Street firms’ revenues and generate new business for some firms that run exchanges. The Federal Housing Finance Agency, which oversees the government-owned mortgage giants, expects them to start using a clearinghouse to trade the swaps by year’s end, according to people familiar with the matter.