PERSONNEL FILE . . . The Northern Virginia Builders Association has named Samuel A. Finz to a new position of chief executive officer of the association. Finz, 45, who has been with International Developers, Inc., succeeds Executive Vice President Robert Cf Johnson, who is leaving the association. At the same time, NVBA President L. Randolph Williams announced that he will empanel a blue ribbon commission to study the 700-member association's role and to work out a plan for reallocating the group's resources to make it a more effective force for its members and the community as a whole . . . The Federal National Mortgage Association has named Rebecca T. Boyd vice president for mortgage-backed securities and C. William Yockey vice president for multifamily activities . . . Robert K. Taylor has been appointed director of the Real Estate Systems Group, a Washington-based company specializing in financial systems, computer consulting and programming for contractors, developers and property managers . . . Robert G. Simon, formerly of the National Corporation for Housing Partnerships, has become a vice president of Boston-based Winthrop Financial Co., Inc. . . . Better Homes Realty has appointed Carole Porter manager of the firm's Alexandria office . . . Eric Lemboris has been named director, real estate management, for Danac . . . The Howard Research and Development Corp. has been named Anthony W. Grabus Jr. vice president and treasurer. . . Diane Moser has been named the firm's corporate relocation representative . . . Frank X. Burke has been appointed property manager for Mount Vernon Realty, Inc.

IN THE BUSINESS . . . The Mason Hirst Cos. have completed the new headquarters building that they developed for the American Association for Guidance and Development. The building, financed through the Alexandria industrial revenue bond program, is in the Landmark area. It will house the office of Mount Vernon Realty as well, and one floor remains available for lease . . . Spaulding & Slye has broken ground for Building Two at Shady Grove Executive Center in Rockville. The structure, the second of seven planned for the center over the next five years, will have 106,000 square feet in four stories . . . One Center Plaza in Baltimore has been topped out. The 12-story, 170,000-square-foot building is 70 percent leased. It is scheduled for occupancy in November.

ON THE MOVE . . . Snider Bros. Property Management has acquired the property management accounts of Wolfe Matan Sheehan Rental Agency. Rick Wolfe, of Wolfe Matan, said his firm will concentrate on consulting in the areas of historic preservation and time sharing . . . P.C. Clearinghouse, Inc., a computer software distribution firm, has leased 9,500 square feet at Oakwood Center, 11781 Lee Jackson Highway in Fairfax. Julien J. Studley was the broker in the transaction.