Fannie Mae and Freddie Mac�??s federal regulator is renegotiating the companies�?? financing plan with the U.S. Treasury Department and may seek an increase to their $400bn federal lifeline before the end of the year, Bloomberg reports.

Treasury and Federal Housing Finance Agency officials are also debating whether to lower the cost of the companies�?? dividend payments on their borrowings from Treasury.

Fannie Mae and Freddie Mac, the largest sources of mortgage money in the U.S., have used $111.6bn of their $400bn in backup financing in less than a year. The companies say their 10 percent annual dividend payment, which comes to about $5bn apiece, costs more than either have earned in most years and adds to their draws on the Treasury.