David Sokol, the man tipped to be the most likely candidate to take-over Warren Buffet's successful Berkshire Hathaway investment firm, unexpectedly resigned after completing Berkshire Hathaway purchase of the chemical company, Lubrizol.

Buffet stated that the purchase had nothing to do with Sokol's resignation. Sokol said the purchase was not connected to his resignation, though according to Buffet, Sokol purchased 96,060 shares at $104 (£64) per share in January, and made around $3m after Berkshire agreed to acquire Lubrizol for $9bn, or $135 a share in March. Sokol had initially advised Buffet to invest in Lubrizol in early January.