Davidson Capital Management of Devon was bought by Boston Private Financial Holdings for an undisclosed amount, the companies said today.

The deal to buy Davidson, which manages $1 billion in assets for high net-worth clients, is Boston Private's entry into the Philadelphia-area market. The publicly traded company, based in Boston, operates a private banking and wealth-management business.

James M. Davidson, founder and chief executive of Davidson Capital, will continue with the firm as chairman. Alvin A. Clay III, who was chief executive of Pitcairn Financial Group in Jenkintown for 14 years, will be its chief executive. Clay also will buy a minority interest in the firm, whose business consists of Davidson Trust Co. and Davidson Investment Counselors. The two units will be merged under the Davidson Trust Co. name.

Shares of Boston Private were up 29 cents to $28.96 in early-afternoon Nasdaq trading.