Buffett's Berkshire buys stakes in Kraft, GlaxoSmithKline

Billionaire investor Warren Buffett's holding company has revealed new investments in Kraft Foods kft and drugmaker GlaxoSmithKline gsk in documents filed with the Securities and Exchange Commission.

Berkshire Hathaway brkabrkb owned 132.4 million shares of Kraft stock and 1.5 million shares of GlaxoSmithKline as of Dec. 31.

The documents also reveal that Berkshire added to its already sizable stakes in Wells Fargo wfc and Carmax kmx.

There were several other changes in Berkshire's $68.8 billion portfolio of U.S. stocks. But the filings do not differentiate between investments Berkshire makes, investments any of its more than 60 subsidiaries make, or investments Buffett himself makes.

Berkshire spokeswoman Jackie Wilson said no one was available to comment Thursday, and the company does not generally comment on its stock investments more than it is legally required to.

The documents filed Thursday are the first ones to mention the Kraft investment, even though Berkshire started buying shares of that company in the second quarter 2007. Berkshire said in the filing that its authority to keep that investment confidential expired Thursday.

Buffett's company often asks the Securities and Exchange Commission for permission to not disclose information that could hurt its trading strategy because the market likes to follow what the company does.

Berkshire owned 311.4 million shares of Wells Fargo at the end of 2007. That's up from the 284.2 million shares of the bank Berkshire owned at the end of Sept. 30.

Buffett's Omaha-based company also bought more shares of U.S. Bancorp usb, parent company of U.S. Bank. Berkshire owned 67.6 million shares of U.S. Bancorp at the end of December, up from 65.5 million shares in September.

Berkshire increased its stake in the nation's largest specialty used-car retailer, Carmax, from nearly 14 million shares in September to 21 million shares at the end of December. Berkshire first invested in the Richmond, Va.-based company sometime in July, August or September.

Berkshire cut its stake in data security firm Iron Mountain irm from more than 9 million shares in September to 4.7 million shares at the end of December. Boston-based Iron Mountain stores and protects data for companies.

Berkshire's 10.96 million shares of American Standard are now shares of Trane tt because the maker of commercial and residential home air conditioners restructured the company last year.

Berkshire's subsidiaries include insurance, clothing, furniture, natural gas, corporate jet and candy companies. Berkshire also has major investments in such companies as Coca-Cola ko and Anheuser-Busch bud.