Securities fraud costs Americans billions of dollars each year, and no population is more heavily targeted by scammers than the elderly. According to the North American Securities Administrators Association (NASAA), here are 10 of the most prevalent types of securities fraud:

Sale of securities by unlicensed individuals. If a securities salesperson is not licensed to sell securities, do not invest. To verify that someone is licensed, call your state securities regulator.

Affinity group fraud. Many scammers use their victims' religious or ethnic identities to gain their trust before stealing their life savings.

Payphone and ATM sales. Some scammers lease payphones or ATM machines to investors for thousands of dollars and promise returns of up to 15%.

Promissory notes. Some fraudsters sell short-term debt instruments issued by little-known or even non-existent companies, promising high returns (even 15% monthly) with little or no risk. (One elderly woman lost her entire $324,000 life savings this way.)

Internet fraud. Scammers use the anonymity and wide reach of the Internet to "pump and dump" thinly traded stocks, peddle bogus offshore "prime bank" investments, and publicize pyramid schemes. Never take anonymous financial advice from e-mail or chat rooms.

Ponzi/pyramid schemes. These scammers promise incredible returns, but the only ones who make money are the ones who set the scheme in motion.

"Callable" CDs. These higher-yielding CDs won't mature for 10 to 20 years, but the seller often misleads the investor to think otherwise. In fact, the bank, not the investor, can "call" or redeem the CD.

Viatical settlements. These originated as a way for terminally ill individuals to receive cash by selling the death benefits of their life insurance policies. But interests in the death benefits of terminally ill patients are generally risky (because of the uncertainties of predicting a person's death) and sometimes fraudulent.

Prime bank schemes. These are often marketed to conspiracy theorists as ways to get triple-digit returns through access to "secret" investments used by the world's elite banks.

Investment seminars. Often the people getting rich are the ones running the seminars