Stocks are mostly flat; oil prices fall

Stocks closed nearly flat 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 staying on the sidelines until after Labor Day.

Cancer drug maker Medivation jumped 20% to $80.42 after pharmaceutical giant Pfizer announced it would buy the company.

The 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% 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 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 Chairwoman Janet L. Yellen is to speak at the Fed’s annual conference in Jackson Hole, Wyo. Although investors do not expect the central bank to raise interest rates at its September meeting, there’s always the possibility that it will.

Some stocks made big moves.

Syngentarose 10.4% to $87.81 after a U.S. national security panel approved the sale of the Swiss agrochemicals company to China National Chemical Corp.

Intersil Corp. jumped 19.8% to $18.74 after the Wall Street Journal said Renesas of Japan is in talks to buy the Milpitas, Calif., chipmaker.

Marathon Oil dropped 6.9% to $15.64 after the oil company said its chief financial officer is resigning and announced several other management changes.

Oil prices fell. U.S. benchmark crude lost $1.47 to close at $47.05 a barrel. Brent crude, used to price oil internationally, declined $1.72 to close at $49.16 a barrel. The drop in energy prices pulled down energy stocks, which lost about 1%.

U.S. government bond prices rose. The yield on the 10-year Treasury note fell to 1.54% from 1.58% late Friday.

Heating oil fell 3 cents to $1.49 a gallon and wholesale gasoline fell 3 cents to $1.48 a gallon. Natural gas rose 9.5 cents to $2.679 per 1,000 cubic feet.

Gold fell $2.80 to $1,343.40 an ounce, silver fell 45 cents to $19 an ounce and copper fell 3 cents to $2.15 a pound.