Warren Buffett's company added a new stake in MasterCard Inc. during the first quarter, but made few other changes in its holdings.
Berkshire Hathaway Inc. filed a quarterly update on its $53.6 billion U.S. stock portfolio with the Securities and Exchange Commission on Monday. The filing shows Berkshire's holdings on March 31, and it revealed 216,000 shares of MasterCard.
The filing also shows Berkshire sold 8,000 of its 29.1 million ConocoPhillips shares.
Buffett manages most of Berkshire's investments himself, but last fall he hired Todd Combs to run a portfolio worth $1 billion to $3 billion. So investors are looking for clues about any investments Combs made since joining Berkshire.
But the quarterly filings don't differentiate between investments Buffett makes or investments any of Berkshire's roughly 80 subsidiaries make.
Berkshire said it received permission from the SEC to keep information about some of its trades confidential, so the company may have been more active than Monday's filing shows.
Buffett's company often asks the Securities and Exchange Commission for the ability to not disclose information that could hurt its trading strategy because the market likes to follow what the "Oracle of Omaha's" company does.
Officials at the Omaha-based company Buffett leads as chairman and CEO did not immediately respond to a request for comment Monday, but they don't typically comment on Berkshire's stock holdings beyond what they are legally required to disclose.
The seemingly quiet first quarter contrasts with the last three months of 2010 when Berkshire sold off several of its smaller investments, including stakes in Bank of America, Comcast, Nestle, Nike, and Lowe's.
Buffett has said most of those stock sales were related to the retirement of the investment manager who bought them. Buffett said he decided to liquidate Lou Simpson's portfolio, so Combs could have a fresh start.
During the first quarter, Buffett did negotiate a $9 billion agreement to buy the Lubrizol chemical company for $135 per share. Lubrizol shareholders are scheduled to vote June 9 on that deal, which includes Berkshire assuming about $700 million in Lubrizol debt.
That deal may have occupied a fair amount of Buffett's time after it was announced March 14 because of the actions of former Berkshire executive David Sokol, who helped make the Lubrizol deal happen. Sokol bought nearly 100,000 Lubrizol shares in early January for about $100 a share even though he knew Lubrizol's board had been discussing Berkshire's possible interest in acquiring the chemical company.
Buffett has called Sokol's actions unethical and inexcusable.
Sokol resigned after disclosing his trades to Berkshire, but he has denied any wrongdoing. Sokol says he left Berkshire to start his own firm.
Besides investments, Berkshire owns clothing, insurance, furniture, utility, natural gas pipeline, brick, carpet, jewelry and corporate jet companies.
Berkshire Hathaway Inc.: http://www.berkshirehathaway.com