NEW YORK (Bloomberg) — Warren Buffett followers who invest like the billionaire instead of with him have been rewarded since the bear market bottomed more than three months ago.

Berkshire Hathaway Inc.'s 19 percent advance since US equity indexes reached their lows on March 9 lags behind 15 of the company's top 20 stock holdings. A $1 million investment mimicking Berkshire's portfolio would have produced a $682,300 profit through yesterday, compared with a $185,900 gain for the same-sized investment in Berkshire shares. Buffett is chairman and head of investing at Omaha, Nebraska-based Berkshire.

Buffett, 78, has seen long-standing equity positions in Wells Fargo & Co. and American Express Co. more than double from their March lows after losing over half their value in the 12 months prior. Companies Berkshire owns outright, meanwhile, had declining sales amid the global recession, and the firm's losses from derivative positions on corporate and municipal debt may not reverse as quickly as those tied to stock markets.

"His investments, because they're based on such fundamental quality and traditional values, are going to continue to do better than the rest of the market," said Frank Betz, a partner at Warren, New Jersey-based Carret Zane Capital Management, which oversees $700 million and owns Berkshire shares. Critics were wrongly declaring that Buffett had "lost his touch" earlier this year, Betz said.

Berkshire is the top shareholder in Wells Fargo, the fourth-largest US bank by assets, and American Express, the biggest credit-card company by purchases. The company is the biggest owner of Goldman Sachs Group Inc., which has surged 93 percent since March 9, and the third-leading investor in US Bancorp, which has climbed 74 percent.

A rally in railroad stocks has also lifted Berkshire's investment portfolio. The company owns 23 percent of Burlington Northern Santa Fe Corp., which has gained 43 percent since March 9, and is among the top 10 holders of Union Pacific Corp. shares, up 50 percent.

The decline in world stock markets at the start of the year contributed to Berkshire's worst loss in at least two decades in the first quarter. The company wrote down derivatives tied to corporate-debt indexes and took a charge on ConocoPhillips shares purchased when oil prices were near their peak.

Berkshire's liability on derivatives at its finance and financial products operations widened to $15.4 billion as of March 31, from $14.6 billion three months earlier. Some of those liabilities, on derivatives tied to four of the world's stock markets, may have reversed in the second quarter as the indexes recovered, said Whitney Tilson, managing director of T2 Partners LLC, a New York-based hedge fund.