Warren Buffett's Berkshire Hathaway has accumulated an 8.6% stake in Kraft Foods , totaling over 132 million shares as of the end of the fourth quarter on December 31.  The stake was worth $4.3 billion on that date. 

At today's closing price of $29.31, it's worth about $3.9 billion.  Kraft shares have been under pressure from rising agricultural commodity prices.  They're down 9.8% in the last month, 11,7% year-to-date, and 14.2% over the last 12 months.

Kraft's current price:

We got a hint of Buffett's interest in Kraft last July when the Wall Street Journal reported Berkshire had acquired a "small stake" in the company.  It was seen at the time as a possible vote of confidence in Kraft's turnaround strategy.  Activist investor Nelson Peltz had been pushing Kraft to sell some businesses to pay for a stock buyback.

Berkshire revealed in SEC filings today that it was buying Kraft as early as the second quarter.  It held69,583,800 shares worth $2.5 billion as of June 30.  Berkshire then increased its stake to107,200,900 shares worth $3.7 billion as of September 30.

Berkshire's reported Kraft stake is its sixth largest by market value, following Coca-Cola ($11.7 billion), Wells Fargo ($8.6 billion), Procter and Gamble ($7.0 billion), American Express ($6.9 billion), and Burlington Northern Santa Fe ($5.7 billion.)

The snapshot of Berkshire Hathaway's portfolio holdings comes from an SEC filing late this afternoon.  Berkshire, like other large holders, reports its portfolio holdings to the government four times each year.  It reflects what Berkshire had on the last day of the fourth quarter, which was December 31, 2007.  It may not be a complete list, as the SEC sometimes gives Berkshire and others permission to temporarily withhold some information to deter copy-cats.

BUFFETT'S OTHER MOVES

Berkshire also says it had 1.5 million shares of the British drug company GlaxoSmithKline, worth about $76 million as of the end of the fourth quarter.   That's a new position for Berkshire.

Glaxo's current price:

Berkshire's CarMax stake jumped to 21 million shares from 14 million at the end of the third quarter.  Shares of the used-car retailer rallied over 6 percent back in November when Berkshire first revealed it had bought a stake.  (Carmax's new Omaha location is now open!)

CarMax's current price:

Berkshire also slightly increased its holdings of:

• Johnson & Johnson: 61,754,448 shares (Dec 31), up 0.2% from 61,607,348 (Sept. 30)
  
  
  
• Sanofi-Aventis: 3,569,905 shares (Dec 31), up 1.1% from 3,530,685 (Sept. 30)
  
  
  
• U.S. Bancorp: 67,581,926 shares (Dec 31), up 3.2% from 65,490,326 (Sept 30)
  
  
  
• Wells Fargo: 289,259,868 shares (Dec 31), up 3.4% from 279,669,568 (Sept 30)
  

Berkshire cut its stakes in:

• Ameriprise: 661,742 shares (Dec. 31), down 54% from 1,448,662 shares (Sept. 30)
  
  
• Iron Mountain: 4,663,900 shares (Dec 31), down 49% from 9,047,850 (Sept. 30)
  

Questions?  Comments?  Email me at buffettwatch@cnbc.com