Older people are especially vulnerable because many have seen their portfolios and income butted hard by a bear market and low interest rates. Some are looking for an edge to regain some losses or find a safe haven. Rising costs, particularly for healthcare, may add to the temptation to try a new investment.

"It is something investors need to always be vigilant about," said Franklin L. Widmann, president-elect of the North American Securities Administrators Association, which has begun an education campaign. "It only takes one bad person to take their money."

The growing number of elderly means there are more potential targets for fraud.

"The vast majority of the wealth in the country lies in the hands of seniors," said John Lawrence Allen, a New York City lawyer and author of "Investor Beware! How to Protect Your Money from Wall Street's Dirty Tricks."

In New Jersey, for example, regulators receive about 300 complaints a year about securities fraud, and field about 2,000 to 3,000 telephone complaints and inquiries.

Experts believe many scams go unreported.

So what can you do to protect yourself?

• First of all, take your time. Don't be pressured into making an investment decision. "There is always another bus," Allen said. "When you hear pressure, when you hear people trying to push you into something, step back and say, 'Let me get a second opinion.' "

• Don't simply rely on your instincts. "It is what gets you in trouble," said the AARP's Hurme. A recent survey by the AARP found that victims of investment fraud were more likely than the general population to trust their hunches.

• Do your homework. References such as Morningstar and Value Line are available at libraries to research securities, Allen said.