Picking stocks and bonds is not supposed to be a roll of the dice, but it turns out that investors can learn a few tricks from card sharks, hustlers and track junkies.

"The stock market is like a gambling casino where the odds are at least probably in your favor rather than against you," said Princeton University economics professor Burton Malkiel, who keeps Dr. Z's Beat the Racetrack on his investing bookshelf, along with his own A Random Walk Down Wall Street.

Some of the world's most prominent investors, including Bill Gross, manager of top-performing bond fund PIMCO Total Return, and Bill Miller, manager of Legg Mason Value Trust in Baltimore, attribute some of their success to studying games of chance.

Many experts hesitate to compare Wall Street to a casino, fearing that would encourage investors to take on big risks.

But those who are recognize the principle successful investors do: You have to know when to hold 'em, know when to fold 'em, know when to walk away and know when to run.

Here's a guide:

The right question: Gamblers and investors need to know which question is the right one to ask, said Legg Mason's Bill Miller.

"If you go to the track, someone will say, 'Who do you like in the third race?' but it's irrelevant who wins. The real question is, What do you make if you win and how much could you lose?" Miller said.

Too many investors never think beyond "Is this a winning stock?" Instead, the question should be, "How much do I think this stock is worth compared with the price it's selling at now?"

The next question should be, "What's the potential downside?"

When to fold: Bet only when the odds are in your favor. That is not often.

"Poker books will tell you exactly the same thing," Miller said. "Mostly, you should fold. In market terms, most stocks underperform because the odds are not in their favor."

When to sell: Take losses early unless you have a good reason to believe an investment will bounce back. Studies of gamblers and investors have found that most people hate to admit they have lost money, so they hold in the belief that they will win again or that the stock will bounce back.

That is a mistake. Hold if your research suggests the stock will rebound, said Bob Bright, a former gambler who founded a day-trading firm, Bright Trading.

Long odds, wrong move: Occasionally, long shots pay off, but so many people are looking for the big score that they bet too much. These are usually losing bets, Malkiel said, whether on a racehorse or a penny stock.