With the stock market going strong, you don’t want to tank your return by making some common investor mistakes.

Which investment had the best return last year? If you’re like most investors, it’s probably the one you just purchased.

“Chasing investment returns is probably the biggest mistake we see,” says Paula Dorion-Gray of Dorion-Gray Investment Advisors.

The problem with buying an investment that went up 50 or 100 percent last year is that the odds are it will probably tank this year.

“The assumption they seem to make is past success will guarantee future success,” says Greg Forsythe, Charles Schwab.

And if you’re avoiding mutual funds altogether because you’re concerned about the after hours trading scandal, investment advisors say you’re making another mistake.

“If you’re 20 or 30 and you’re contributing to your 401(k) plan, you’re going to go through a lot of peaks and valleys,” Dorion-Gray says.

But you have the time to let your investment recover. Still, you have to know when to fold ’em.

“When you don’t have a sell discipline, you’re vulnerable to letting emotion drive the process,” Forsythe says.

Trusting the wrong advisor can be another mistake.

“I trusted the advisor to give me advice and the one stinker in the portfolio was a managed stock account. And the minimum investment was $100,000 and that one fund, the fees were higher than the gains,” says Nancy Pease, investor.

At least Nanyc Pease’s investment advisor chose an investment. Noel and Bobbie Deitrich’s advisor seemed paralyzed with fear.

“She made one really fatal mistake. We said what should we do? What should we be investing in at this point in time? Her answer was I haven’t a clue?” Noel Deitrich says. “We have to reevaluate how much we have in cash.”

Thinking you need everything in cash or bonds on the day you retire is a major mistake investors make with their retirement money. Instead of moving everything to bonds, you should always have something invested in the stock market.

“We have clients in their 70s and 80s who are still in the stock market to some degree because they could live to be 110,” Dorion-Gray says.

And the best investments will make sure you’re prepared for anything.