WARSAW, Ind. (AP) — Orthopedic device maker Zimmer is buying privately-held Biomet for about $13.35 billion in a move aimed at helping expand its product offerings and services.

Even though it is the buyer, Zimmer shares rose more than 17 percent in morning trading Thursday. Shares of companies that make an acquisition often fall when they announce a deal because of the costs. A rise suggests some investors like the deal.