Q. I thought Bill Miller was supposed to be a genius. What happened to Legg Mason Value Trust fund? -- M.B., via the Internet

A. Fifteen consecutive years of outperforming the Standard & Poor's 500 ended abruptly after 2005, and the well-known fund hit the wall.

It was stuck with a concentrated portfolio that included a big stake in financial stocks such as Freddie Mac, Citigroup Inc. and Merrill Lynch & Co. It also owned homebuilders, some disappointing technology plays and no energy stocks.

Investors noticed the tanking results. A combination of withdrawals and declining value knocked this fund's total assets from $17 billion at the start of this year to less than $10 billion.

Legg Mason Value Trust fund (LMVTX) is down 40 percent over the past 12 months, down 9 percent in annualized return over the past three years and virtually flat over the past five years. All three results rank in the lowest percentile of large growth and value funds.

"Fundamentally the fund's approach is sound, and despite some mistakes, we're still impressed by its analysis," said Greg Carlson, analyst with Morningstar Inc. in Chicago, who considers it a core holding for patient investors who can handle volatility. "We recommend it and note that it recently has done well as stocks of banks and other financials have shown improvement."

Bill Miller has been portfolio manager since 1982 and Mary Chris Gay co-manager since 2006. Miller seeks firms trading inexpensively based on his estimates. Although he often goes for turnaround plays, he doesn't avoid some pricey traditional growth companies.

The portfolio usually has 30 to 50 names, and Miller is willing to let favored names run a long time. Its concentrated nature can amplify blowups. Miller runs $30 billion in money overall, which could hamper his ability to tend to this particular portfolio.

Financial services and consumer services each represent about 22 percent of Legg Mason Value Trust's portfolio. Largest holdings are Amazon.com Inc., AES Corp., JPMorgan Chase & Co., Aetna Inc., UnitedHealth Group Inc., Yahoo Inc., eBay Inc., Sears Holdings Corp., General Electric Co. and Freddie Mac.

The "no-load" (no sales charge) fund requires a $1,000 minimum initial investment and has an annual expense ratio of 1.68 percent.

Q. What exactly is a stock's yield? How is it calculated? As a new investor, how does it matter to me? -- V.A., via the Internet

A. A dividend is a payment made to shareholders. Mature businesses such as utilities tend to pay higher dividends, while growth companies such as many technology firms often plow excess earnings back into the firm.

A stock's dividend yield is an annual percentage calculated by dividing the firm's annual dividend by its share price. For example, a $50 stock with $2 dividend has a yield of 4 percent.

"Yield matters most to investors hoping to generate income from their portfolio or protect themselves from volatility," said David Bendix, certified financial planner with Bendix Financial Group in Garden City, N.Y. "If a stock is down but you're receiving a dividend, it cushions your losses."

Because yields go up when stock prices go down, which is frequently occurring in the current market, a high yield can merely be a function of a low stock price, Bendix said.

"Investors should also be aware that a company paying a high dividend may not be reinvesting as much back in the company," Bendix said. "That could mean less long-term growth potential."