It's been a tough first four months of the year for Bill Miller of the Legg Mason Value Trust (LMVTX), famous for his 15-year run beating the S&P 500. Even after a 4.12% bounce in his fund's net asset value on Thursday, he's down 14.95% for the year. One major culprit? His stake in Bear Stearns (NYSE: BSC) that was once worth more than $200 million, making the fund one of the firm's largest shareholders.

According to the Wall Street Journal (subscription required), Miller's performance reminds him of his tough run that began the 1990s: "Back then, a similar crisis was unfolding in financial markets and Mr. Miller eventually swooped in to buy money-center banks like Chase Manhattan and Citicorp that he thought were underpriced, as well as insurance companies and mortgage lenders. Financials made up as much as 45% of Mr. Miller's portfolio by the mid-1990s, and helped drive his 15-year winning streak as they rallied over the years."

Mr. Miller told his fund's shareholders that "the past two years are a lot like 1989 and 1990," and there's a "reasonable probability the next few years will look like what followed those years."

Maybe so. But investors should be wary of the fact that a big part of Miller's outperformance stemmed from his exposure to financial stocks and now that same exposure is dragging his fund into the lowest echelons of mutual fund performance.

Is the Legg Mason Value Trust just a glorified bet on the bounce back in financials? If so, investors may want to tread carefully, as Miller has been wrong about the sector for awhile.