David Sokol worked at Berkshire Hathaway for legendary investor Warren Buffett, who is renowned not only for his investment skills but also for his ethics. Bankers suggested to both Sokol and the CEO of Lubrizol that the company might be a good buy for Berkshire. Sokol then found out that the CEO of Lubrizol planned to ask his board for permission to approach Berkshire about a possible acquisition. Sokol purchased $10 million worth of Lubrizol stock before recommending Lubrizol to Buffett. Sokol mentioned to Buffett "in passing" that he owned shares of Lubrizol. Buffett did not ask any questions about the timing or amount of Sokol's purchases. Sokol made a $3 million profit when Berkshire acquired Lubrizol. Did Sokol violate insider trading laws? Did he behave ethically? What are Buffett's ethical obligations?