Aug. 14 (Bloomberg) -- Berkshire Hathaway Inc., the investment firm run by Warren Buffett, bought stakes in Dow Jones & Co. and Bank of America Corp. and more than quadrupled its holdings of health insurers UnitedHealth Group and WellPoint Inc.

Berkshire hadn't previously disclosed the stakes in Dow Jones, owner of the Wall Street Journal, and Bank of America, the second-largest U.S. bank, though it's unclear when the company acquired the positions. As of June 30, Berkshire held 2.78 million shares of Dow Jones and 8.7 million shares of Bank of America, the Omaha, Nebraska-based firm said in a filing with the U.S. Securities and Exchange Commission today.

Berkshire owns the Buffalo News and is the largest shareholder in Washington Post Co. Buffett said in May he wasn't interested in acquiring New York-based Dow Jones, which was evaluating a bid from Rupert Murdoch's News Corp. that's since been accepted. The $60-a-share offer was 65 percent higher than Dow Jones' closing price on April 30, the day before Murdoch's bid was made public.

``There's no way he would have bought this company outright, especially in a bidding war, but he loves arbitrage,'' said Mohnish Pabrai, who oversees about $600 million, including shares of Berkshire, as managing partner of Pabrai Investment Funds in Irvine, California. ``He probably expected all the egos to come in and a lot more bidding to happen.''

Buffett, 76, has run Berkshire for more than four decades, transforming a failed textile manufacturer into a holding company with a $170 billion market value and interests in dozens of industries as diverse as insurance and candy making.

Copycat Investing

It's difficult to determine exactly what Berkshire owns at any given time because Buffett sometimes requests the SEC's permission to keep changes in holdings temporarily confidential to avoid copycat investing. A review of the company's quarterly SEC filings showed Berkshire hadn't disclosed any stakes in Dow Jones or Bank of America for at least the past five years, though Berkshire may still amend filings for past periods.

There is no question that Berkshire's additional health insurance holdings were purchased during the second quarter, however. Berkshire held 4.8 million shares of Minnetonka, Minnesota-based UnitedHealth, the largest U.S. health insurer, on June 30, up from 1.02 million on March 31, the filing shows. It ended June with 4.2 million shares of Indianapolis-based WellPoint, No. 2 in the industry, up from 979,700 in March.

Berkshire also increased its holding of Johnson & Johnson, the world's largest health-products company, 9.2 percent to 53.1 million shares, and quadrupled its number of American depositary receipts in Sanofi-Aventis SA, France's largest drugmaker, to 3.53 million. Buffett's been building the stake in New Brunswick, New Jersey-based Johnson & Johnson since the start of 2006.

Union Pacific, Norfolk

Berkshire, the biggest shareholder in Burlington Northern Santa Fe Corp., omitted information on two other railroad companies, Union Pacific Corp. and Norfolk Southern Corp. The company held 10.5 million shares of Union Pacific and 6.36 million shares of Norfolk Southern at the end of March and said today it was keeping any changes in those positions confidential.

Higher fuel prices have made the rail industry more competitive with trucks, Buffett said at the company's annual meeting in May. Berkshire added 4.38 million shares of Burlington Northern during the second quarter, bringing its holding to 39 million shares, it said in a separate filing last week.

In addition to disclosing the stake in Charlotte-based Bank of America, Berkshire increased holdings of Wells Fargo & Co. and U.S. Bancorp and slashed stakes in Western Union Co. and Ameriprise Financial Inc.

H&R Block, Pier 1

It increased San Francisco-based Wells Fargo, the second- biggest U.S. home lender, 11 percent to 257.7 million shares, and Minneapolis-based U.S. Bancorp, the sixth-largest U.S. bank, 59 percent to 37.1 million shares.

The holding in Englewood, Colorado-based Western Union, the biggest U.S. money-transfer business, fell 68 percent to 3.2 million shares, while the stake in Minneapolis-based Ameriprise Financial Inc., the investment adviser spun off from American Express Co. in 2005, dropped 41 percent to 2.52 million shares.

The company didn't report any holdings of retail furniture company Pier 1 Imports Inc. or tax preparer H&R Block Inc. At the end of March, it held 1.48 million shares of Forth Worth, Texas-based Pier 1 and 1.25 million shares of Kansas City, Missouri-based H&R Block, an earlier filing showed.

Berkshire trimmed its position in Bermuda-based Tyco International Ltd., the world's biggest maker of fire and security systems, 37 percent to 6.3 million shares.

To contact the reporters on this story: Josh P. Hamilton in New York at jphamilton@bloomberg.net; Erik Holm in New York at eholm2@bloomberg.net

Last Updated: August 14, 2007 21:51 EDT