(New York Post) An activist investor is probing whether hedge funds are using a controversial stock-trading tactic to tip the vote in favor of pharma giant Bristol-Myers Squibb’s $74 billion deal to buy rival Celgene, The Post has learned. Starboard Value — whose boss Jeff Smith has blasted the merger as too expensive for Bristol-Myers shareholders — has launched a books-and-records request, partly to determine whether an upcoming shareholder vote on the cash-and-stock merger could be swayed by so-called “empty voting,” sources told The Post.