Warren Buffett's Berkshire Hathaway Inc said on Friday it had modestly raised its stakes in Wells Fargo and US Bancorp , two banks whose market values have fallen dramatically.

Buffett, who had hinted at Berkshire's annual meeting earlier in the month that he would like to add to his positions in the two banks at their current prices, raised his stake in Wells by 12.4 million shares as of March 31, for a total of about 6.5 percent of its outstanding shares. Berkshire was already Wells' biggest shareholder.

Berkshire raised its U.S. Bancorp stake by 1.5 million shares, reversing some sales in the prior quarter and giving Berkshire a total of about 3.7 percent of U.S. Bancorp.

Both banks' shares fell to decade lows in the first quarter.

Buffett, who oversees investment decisions for Berkshire, also added about 3.9 million Johnson & Johnson shares, after cutting his company's holding of the health-care company by more than half to 28.6 million during the prior quarter to raise funds for other investments.

The changes were not dramatic, said Morningstar analyst Bill Bergman. They did not do a lot here, which probably reflects that he is seeing more opportunity in bond markets.

Berkshire also bought more shares in two railroads -- Northern Santa Fe Corp and Union Pacific Corp -- but left many holdings, including Coca-Cola Co and Procter & Gamble

, untouched.

Buffett is famous for taking long-term bets on companies he thinks will produce superior results over time.

He has a timeframe that transcends near-term swings, said Thomas Russo, a partner at Gardner Russo & Gardner, adding that Buffett was holding tight to many investments that might be battered a bit by recent currency fluctuations. Berkshire is the Lancaster, Pennsylvania, firm's largest holding.

Berkshire disclosed a lower stake in oil company ConocoPhillips , something investors had expected after Berkshire took $1.9 billion in write-downs from this investment in the first quarter.

Buffett said earlier this month that ownership of Conoco had fallen further since the end of March. He has referred to Berkshire's investment in Conoco, about $7 billion, as a major mistake.

The company also cut its holdings of Constellation Energy and UnitedHealth Group .

Berkshire disclosed its holdings in a U.S. Securities and Exchange Commission filing.

The quarterly report excludes holdings on non-U.S. exchanges. It may also exclude other investments for which Buffett has received SEC permission to not immediately disclose. The regulator sometimes lets Buffett delay disclosure so investors cannot copy him while he is buying.

Berkshire, one of America's most revered companies, has been hurt in recent quarters by the falling value of its stock investments, as well as long-term derivatives contracts tied to stock market indexes and the credit quality of junk bonds. It disclosed its first quarterly loss since 2001 in the first quarter.

The company's shares have slid about 40 percent from their 52-week high last September 19. On Friday, Class A shares closed down $480, or 0.54 percent, at $89,120 on Friday. Its Class B shares also fell to $2,899.80, a 0.67 percent decline.

(Reporting by Lilla Zuill; Editing by Matthew Lewis, Gary Hill)