Warren Buffett has returned to the M&A market. The Omaha b illionaire’s investment vehicle Berkshire Hathaway Inc. agreed on March 14 to pay $9 billion for Lubrizol Corporation and assume another $700 million in Lubrizol debt. The specialty chemicals company’s stockholders will receive $135 per share in cash, a 28 percent premium to Lubrizol’s closing price on March 11, the last trading day before the deal was announced.

David Sokol, one of Berkshire’s senior executives, brought the deal to Buffett, but he resigned abruptly on March 28 because Sokol had bought about $10 million in Lubrizol stock at slightly above $100 per share before advocating for the deal with Buffett. Both Buffett and Sokol denied that Sokol had broken the law.