Proskauer Rose has expanded its antitrust group with the addition of Helene D. Jaffe as a partner and co-head of the practice. Ms. Jaffe, who concentrates on the transactional, counseling and litigation aspects of antitrust issues, was global co-head of the antitrust/competition practice at Weil, Gotshal & Manges.

• Former Nassau County surrogate John B. Riordan has joined Reisman Peirez Reisman & Capobianco in Garden City as senior counsel in the trusts and estates department.