More than two dozen cases have been reported in the state so far.
Gail Gawenda, a spokeswoman for the state Department of Financial Institutions, says an unknown caller will leave a supposedly misdialed message for a friend.
She says the messages advise them to jump in on a hot stock tip in lightly traded and obscure companies, but she says the message is no accident.
Gawenda says the companies are difficult to research. She says authorities don't believe the companies are involved, but rather an investor hoping his stock value goes up.
The U.S. Securities and Exchange Commission is investigating the scam.