The regulator for Fannie Mae (FNM) and Freddie Mac (FRE) defended the retention pay promised to key employees after the mortgage giants were seized by the government.

"These institutions are so important to the United States at this point," Federal Housing Finance Agency Director James B. Lockhart said Wednesday. "We have to make sure that the people who are there are doing the job."

When it took over the mortgage giants in September, the government threw out their chief executives and their boards. Several top executives left the firms in the following weeks and months. David Moffett, who was installed as chief executive of Freddie after the takeover, stepped down in February after just a few months in the job.

Lockhart noted that pay generally has declined sharply at the companies, with many employees earning half of what they owned before the firms were put into conservatorship.

"My view is that we have to be careful and not give excessive compensation," he said.

-Jessica Holzer, Dow Jones Newswires; 202-862-9228; jessica.holzer@dowjones.com