Buffett trimmed Berkshire's holdings in riskier businesses that have uncertain futures, such as newspapers, healthcare companies, and credit ratings agencies in favor of more stable long-term picks such as Wal-Mart Stores Inc. (NYSE: WMT) and ExxonMobil Corp. (NYSE: XOM).
The 13-F filing showed that as of Sept. 30 Berkshire had increased its Wal-Mart holdings by almost 90% over the summer, adding 18 million shares worth nearly $1 billion.
Berkshire Hathaway Inc. (NYSE: BRK.A, BRK.B) acquired railroad Burlington Northern Santa Fe Corp. (NYSE: BNI) in a deal valued at $44 billion, the largest in Berkshire's history.
Berkshire, which already owns 22.6% of the company, will pay $100 per share in cash and stock for the remainder of Burlington's business. The offer values Burlington stock at a 31.5% premium to its Monday close. The deal, expected to close in the first quarter of next year, includes $10 billion in Burlington debt.