NEW YORK (AP) — Stocks are headed for a lower opening as investors assess the economic fallout of a massive earthquake in Japan.

The devastating earthquake and tsunami along Japan's northeast coast killed thousands of people and led to what is expected to be billions in dollars of damage. That raised fears of a slowdown in the world's third-largest economy.

Oil prices fell $1.57 to $99.59 a barrel Monday, and Japan's central bank pumped a record $184 billion into money market accounts to encourage bank lending.

Japan's benchmark Nikkei 225 index fell 633.94 points, or 6.2 percent, to 9,620.49 — its lowest level in four months. The decline wiped out this year's gains.

In the U.S., Warren Buffett's Berkshire Hathaway Inc. said it would purchase chemical company Lubrizol for $9 billion in cash. Berkshire will pay $135 per share, a 28 percent premium to Lubrizol's closing stock price Friday of $105.44. Berkshire's Class B shares fell 1 percent on the news in pre-market trading, while Lubrizol rose 27 percent.

Ahead of the opening, Dow Jones industrial average futures are down 78, or 0.7 percent, at 11,925.

Standard & Poor's 500 futures are down 9, or 0.7 percent, at 1,292. Nasdaq 100 futures are down 18, or 0.8 percent, at 2,285.

Bond prices are rising, sending yields lower. The yield on the 10-year Treasury note fell to 3.38 percent from 3.41 percent late Friday.

Cephalon fell 2 percent in pre-market trading after a federal court overturned two of the patents on its painkilling drug Fentora. That could allow competitors to start selling cheaper generic versions of the drug soon.

Later this week, investors will get economic reports on consumer prices, industrial production and home construction.