Wall Street firm Morgan Stanley, under fire for lagging stock performance and tepid earnings growth, has named David Heleniak, a lawyer specializing in mergers and acquisitions, as vice chairman of the company and head of its legal division.

Heleniak, 59, the senior partner at law firm Shearman & Sterling LLP, has had a hand in some of the largest merger deals in recent history, including Citicorp’s merger with Travelers Group and Viacom Inc.’s purchase of Blockbuster Inc. and Paramount.