Related topics: Michael Brush, investing strategy, mutual funds, stocks, stock market

Now that stocks are coming back, you may be tempted to call a broker to get back in the game.

Be careful. Although the market cops have cracked down on the industry for its shenanigans since the tech and housing bubbles, there are still a lot of secrets your broker will never volunteer.

And what you don't know can hurt your returns.

Now, you're unlikely to be so unfortunate as to wind up with the likes of former Citigroup (C, news) broker William Joseph Boyle, who regulators say took $531,000 in savings from a 64-year-old nun last year. Or former Morgan Stanley (MS, news) broker John Edward Mullins, who was accused of taking $11,000 from a 97-year-old widow in a nursing home and using it to buy wine at a posh restaurant, clothes and a vacation at a Four Seasons Hotel in London. (In settling their cases, these former brokers neither admitted nor denied the allegations.)

But the hard, cold reality is that even honest brokers can find themselves entangled in a complex mesh of conflicts of interest. They have more to consider than your best interests when advising you on investments.

So while you're probably turning to a full-service broker -- as opposed to, say, an online outfit that just makes trades -- in the belief that you'll find a helpful soul who is well-trained in investing, you're also talking to a salesman.

To get the lowdown, I talked with regulators and other experts, including a former industry insider who spent 18 years in the field, rising high enough that he recruited and trained hundreds of other brokers.

"I escaped the dark side," says Dave Loeper, who now advises investors at Wealthcare Capital Management and has summed up much of what he learned in a book called "Stop the Investing Rip-off."

Based on what these experts had to say, here are eight secrets your broker won't tell you:

No. 1: I was hired for my people skills and charm, not my investing skills.

"The skill set that qualifies a person to be a broker is nothing like what the public perceives," Loeper says. "You are more likely to become a broker if you were successful selling used cars than if you have a financial-analysis degree."

Brokers have to be polished and have good persuasion skills. They also have to be thick-skinned, aggressive, capable of dealing with rejection and good at coercion. Knowledge about financial products comes much lower on the list of traits hiring managers look for in brokers.

And beware of the nice certificates on the wall. They might not be worth the paper they're written on. For example, the title of certified annuity adviser may make you think you're talking with someone who knows all the ins and outs of annuities. But the title requires only about two days of self-directed study to attain.

"It's important for investors to understand that not all professional designations are created equal," cautions John Gannon, who runs investor education for the Financial Industry Regulatory Authority, or FINRA, which oversees brokers. Likewise, be skeptical of ratings like "Top 100 Advisers," because a lot of those rankings are a charade, he says.

As you might suspect, brokers selling financial products they don't know much about can lead to huge disasters. During the credit bubble, thousands of investors bought products called auction-rate securities from major brokerages like Merrill Lynch, Deutsche Bank (DB, news) and Citigroup, thinking they were relatively safe alternatives to money market funds.

When the markets for these securities froze during the credit meltdown, investors could not get their money out. A big part of the problem was that "there were a lot of brokers who didn't understand what they were selling," says James Angel, a professor of finance at Georgetown University's McDonough School of Business. Since then, the brokerages above have spent millions bailing out their investors in these products.

Unfortunately, examples of brokers pushing products they don't understand -- with disastrous results for customers -- pop up all the time. Just a few months ago, for example, FINRA fined HSBC Securities $375,000 for putting unsophisticated retail investors into products called inverse floating-rate collateralized mortgage obligations, a highly complex play on repackaged mortgage debt. In settling the case, HSBC made up $320,000 in losses sustained by 43 investors.

(These brokers and brokerages, like all the ones I mention here because they were fined and sanctioned by FINRA, neither admitted nor denied details provided by regulators in settling their cases.)

How to fight back: Be sure you read all the paperwork and fully understand anything you are investing in. If it seems too complicated, stay away. To check on the quality of broker credentials, look here.