Stocks lower on quiet day

NEW YORK (AP) - Stocks closed slightly lower in quiet trading Monday after drifting most of the day between gains and losses. Energy companies fell along with the price of oil while biotechnology and drug companies rose after Pfizer announced it was buying a cancer drug maker.

Trading remained subdued, as it has been for most of the month, with many investors remaining on the sidelines until after Labor Day.

The Dow Jones industrial average lost 23.15 points, or 0.1 percent, to 18,529.42. The Standard & Poor's 500 index lost 1.23 points, or 0.1 percent, to 2,182.64 and the Nasdaq composite rose 6.22 points, or 0.1 percent, to 5,244.60.

Cancer drug maker Medivation jumped $13.26, or 20 percent, to $80.42 after pharmaceutical giant Pfizer announced it would buy the company for $14 billion, or $81.50 a share. Pfizer is buying Medivation for its heavily used prostate cancer drug Xtandi, which generates roughly $2 billion in sales a year.

The Medivation deal pushed other biotechnology stocks higher as well, helping the Nasdaq do better than the S&P 500 and the Dow. Regeneron Pharmaceuticals, Vertex Pharmaceuticals and Alexion Pharmaceuticals all rose 3 percent or more.

Monday's trading was extremely light. Roughly 2.73 billion shares changed hands on the New York Stock Exchange, the lightest trading volume so far this year. It is typical for trading to slow in August, with many traders and investors finishing up their summer vacation plans.

Investors have had little to go on for the last couple of weeks. Second-quarter earnings reports are effectively over, and the next major piece of economic news does not come until Friday, when Federal Reserve Chair Janet Yellen will speak at the Fed's annual conference in Jackson Hole, Wyoming.