Legg Mason Value Trust manager Bill Miller built his reputation -- and the fortunes of his investors -- by beating the benchmark S&P 500 for 15 years, a streak that ended in 2006.

But since that run ended, the fund has struggled mightily with bad bets on companies like Countrywide Financial (NYSE: CFC), Bear Stearns (NYSE: BSC), and Yahoo! (NASDAQ: YHOO). Now Miller's investors are questioning his philosophy, and so is is the legend himself.

A big part of Miller's brilliant track record was his belief in focus investing -- concentrating his bets on a few stocks rather than a bunch. The Legg Mason Value Trust holds just 35 stocks. But according to the New York Times, that strategy is now being reconsidered. Miller said that "The question we are asking ourselves is: Should we think more broadly now about probability, about high-impact events and protecting against them by having broader exposure to the market?"

I seriously doubt that that's the right strategy. Miller is universally acknowledged to be a great stock picker -- diluting his influence by building a portfolio consisting of his 200 best ideas instead of his 35 best sounds like a sure road to mediocrity.

The larger point is this: After a 15-year streak of greatness, Miller has hit a rough patch. Two years of underperformance doesn't change 15 years of greatness, and this is a bad time to consider changing the strategy that led to his track record.

Bill Miller considers move away from focus investing -- why? originally appeared on BloggingStocks on Sun, 11 May 2008 11:10:00 EST. Please see our terms for use of feeds.