David Sokol, protege to, and heir apparent to, Warren 'the Omaha Oracle' Buffett, resigned abruptly from Berkshire Hathaway following disclosure that he had purchased shares in Lubrizol shortly before Berkshire agreed to buy the lubricant company.  Mr. Sokol has said he did nothing wrong.  Warren Buffett agrees.  On Wednesday, Mr. Mr. Buffett said, "Dave's purchases were made before he had discussed Lubrizol with me and with no knowledge of how I might react to his idea." 

A government inquiry will decide the answer.  In the meantime, NYT Dealbook's Ben Protess and Andrew Ross Sorkin offer this timeline of events, including Sokol’s trading in Lubrizol and Berkshire’s announcement about the acquisition.

Dec. 14:   Mr. Sokol purchases 2,300 shares of Lubrizol, according to a statement issued by Mr. Buffett.

Dec. 17:   A Citi banker calls Mr. Hambrick to inform him of Berkshire’s possible interest in the company, the Lubrizol regulatory filing said. Mr. Hambrick says he would relay the information to his board of directors.

Dec. 21:   Mr. Sokol sells his 2,300 shares of Lubrizol, according to Mr. Buffett. Shares of the company closed at 109.28, roughly the mark where Mr. Sokol purchased his stake days earlier. Mr. Sokol told CNBC on Thursday that he sold the shares for tax purposes.

Jan. 5 to 7:   Mr. Sokol accumulates 96,060 Lubrizol shares worth nearly $10 Million, Mr. Buffett said.

Jan. 6:   Lubrizol’s board holds a “special meeting” to discuss Berkshire Hathaway’s possible interest in the company, according to the Lubrizol filing. The board agreed to hire attorneys to advise on a possible deal.

Jan. 7:   Mr. Hambrick meets with the law firm Jones Day to discuss Berkshire’s interest, the filing said.

Jan. 14:    Mr. Sokol and Mr. Hambrick talk on the phone about the “corporate cultures and philosophies” at their respective companies, according to the filing. They agreed to meet in person later in the month.

Jan. 14 or 15:   Mr. Sokol mentions a possible Lubrizol deal to Mr. Buffett for the first time, according to Mr. Buffett. Mr. Sokol made a “passing remark” to Mr. Buffett about his stake in Lubrizol, Mr. Buffett said.

Sometime between Jan. 15 and Jan. 24:   Mr. Buffett indicates “skepticism” about making a bid for Lubrizol in a note to Mr. Sokol, according Mr. Buffett’s statement.

Jan. 25:    Mr. Sokol and Mr. Hambrick meet for dinner in Cleveland. They discussed Lubrizol’s “overall business and past and expected financial performance,” according to the regulatory filing. They did not discuss a possible price for the deal.

Shortly after Jan. 25:   Mr. Buffett “warmed to the idea” of a Lubrizol deal. “Only after Dave reported on the January 25 dinner conversation with James Hambrick did I get interested in the acquisition of Lubrizol,” he said.

Feb. 8:    Mr. Hambrick and Mr. Buffett meet in Omaha to discuss a possible deal. Mr. Buffett said Berkshire would like to “offer to buy all of the outstanding shares of Company common stock for $135.00 per share in cash,” according to the filing.

March 13:   Berkshire’s board unanimously approves the merger.

March 14:   Berkshire announces a deal to buy Lubrizol for $9 billion.

March 19 or just before:   Mark Hamburg, senior vice president and chief financial officer at Berkshire Hathaway, tells Mr. Buffett of the details of Sokol’s investment in Lubrizol.

March 19:     Mr. Buffett leaves on a trip to Asia

March 27: Mr. Buffett and Mr. Sokol discuss “various operating matters,” Mr. Buffett said, adding that he “received no hint of his intention to resign.”

March 28: Mr. Sokol’s assistant delivers his letter of resignation to Mr. Buffett.

March 30: Mr. Buffett publicly discloses Mr. Sokol’s resignation

[NYT DealBook, 3/31, "Sokol, Buffett and the Lubrizol Trades"]