Capitol Publications Inc. of Arlington, producer of Education Daily and U.S. Oil Week, acquired Kephart Communications of Alexandria late last week for an undisclosed sum, said John D. Wills, president of Capitol.

It's a case of the little fish swallowing the bigger fish. Kephart, which publishes three consumer newsletters, does about $8 million in sales annually. According to Wills, that's more than Capitol's sales, but he declined to specify his firm's sales or profits because it is privately owned. Capitol's plant and staff are larger than Kephart, however.

Kephart, founded in 1974 by Robert D. Kephart, publishes Personal Finance, Tax Angles and Survival Tomorrow, which have a combined circulation of 150,000, according to Capitol. Also acquired by Capitol were Kephart's house advertising agency, Media Mart Advertising; a direct-mail division and a book-publishing division.

Wills said he wanted the transition of ownership to proceed smoothly, with as little disruption as possible for Kephart's approximately 35 employes. Robert Kephart and one of the firm's vice presidents, Janet Fouse, have told Wills they will not be joining the combined operations, Wills said.

Two of Capitol's executives will move to Kephart immediately. Elizabeth Early will become vice president for operations, Wills said, and Brian Smith will be assistant to the publisher. Wills will run both Kephart and Capitol for the time being.

"Capitol Publications is built solidly on one basic premise: meeting the information needs of top decision-makers in business, government, academia and the professions," Wills said. "All three of Kephart's publications are written for a consumer audience. It's a new focus for us, a challenge."

Capitol, which recently moved from the District to Rosslyn, publishes 34 newsletters.