WASHINGTON (AP) _ Securities and Exchange Commission Chairman Richard Breeden's announcement Thursday that he was stepping down by April 15 increases pressure on the Clinton administration to name his successor.

A source who spoke on condition of anonymity said the administration planned to announce its final choice in early February but that was pushed back by the delay in selecting an attorney general.

Most frequently mentioned as the administration's top choices to fill the SEC post are Consuela Washington, securities counsel for the House Energy and Commerce Committee, and James Cheek III, a Nashville, Tenn., securities lawyer.

Ms. Washington, 44, has the backing of the committee's powerful chairman Rep. John Dingell, D-Mich. Cheek, 50, is said to have the support of Vice President Albert Gore, a Tennessean.

Ms. Washington would be the first woman and first black to head the agency if she is picked. A native of Chicago, she is a Harvard law school graduate and former SEC attorney.

''She's at the crossroads of securities regulation. If you're serious about talking about it, you've got to see Consuela,'' said John W. Bachmann head of the St. Louis, Mo.-based brokerage firm Edward D. Jones & Co.

Ms. Washington served for more than two years in the SEC's Division of Corporation Finance, which monitors how companies raise money by selling stock and bonds to the investing public.

In 1979 she became a staffer on the House Interstate and Foreign Commerce Committee, before joining Dingell's staff in 1981.

''She is tough. She knows what she's talking about. She really zeroes in on the heart of the matter,'' said Nancy Smith, director of New Mexico's Securities Division and a former congressional staffer herself.

Before entering government service, Ms. Washington, served for a year in the corporate law department of Milwaukee, Wis.-based heavy equipment maker Allis-Chalmers Corp.

Some SEC staffers believe that with a Dingell protegee as head of the commission they will be hit with fewer critical letters, known as ''Dingellgrams,'' from the Michigan Democrat seeking information or demanding investigations.

But industry sources said Ms. Washington's ties to Dingell have raised concerns about too much congressional influence over an independent agency.

Cheek is a partner at the Nashville firm of Bass, Berry & Sims. A 1964 graduate of Duke University, Cheek got his law degree from Vanderbilt University in 1967 and the following year received a masters degree from Harvard.

''Jim Cheek is a very able guy and he is not only an able securities lawyer but he also knows the industry,'' said Joseph Hardiman, president of the National Association of Securities Dealers, which regulates the over-the- counter stock market.

Cheek has been chairman of the New York Stock Exchange's legal advisory committee since 1989 and served as chairman of the American Bar Association's Committee on Federal Regulation of Securities from 1987 to 1991.

Other names mentioned as possible contenders include: Washington lawyers John F. Olson and Richard M. Phillips; Merrill Lynch & Co. vice chairman Stephen L. Hammerman; and two current SEC commissioners, Richard Roberts, a Democrat and Mary Schapiro, an independent.