Among stocks making big moves:
—Drugmaker Merck fell more than 3 percent, down $1.42 to $41.83. Its fourth-quarter profit suffered because of competition from generic medicines against its blockbuster allergy drug Singulair.
— Insurance company MetLife rose more than 2 percent, up 86 cents to $38.20, after saying it plans to buy the largest private pension fund administrator in Chile.
— Zoetis, an animal health business that Pfizer just spun off, made its debut on the stock market. It shot up 19 percent, rising $5.01 to $31.01.
AP Business Writer Matthew Craft contributed to this report.