GOOD START: Drugmaker Pfizer's initial public stock offering of its animal health business, Zoetis, raised $2.2 billion, the largest IPO by a U.S. company since Facebook Inc. raised $16 billion last May. Shares jumped 19 percent from their initial $26 price, closing at $31.01.

PFIZER STAKE: For now, Pfizer Inc. retains ownership of at least 80 percent in Zoetis Inc., which has annual sales of $4.2 billion.

GAME PLAN: Zoetis CEO Juan Ramon Alaix plans to keep developing new medicines and vaccines for pets and livestock, creating new versions and combinations of existing products, and expanding in emerging markets.