The North American Securities Administrators Association is warning investors to carefully monitor their online trading accounts in the wake of “hack attacks” in which predators have broken into customer accounts at online brokerages in the US and Canada and made unauthorized trades worth millions of dollars.

The NASAA says that federal and industry authorities are investigating recent cases in which hackers gained access to customer accounts at several large online brokers and used the customers’ funds to buy certain thinly traded microcap securities. The hackers appeared to be running a “pump and dump” scheme, trying to drive up share prices so they could sell the stocks at a profit.

These scams typically begin with a hacker obtaining customer passwords and user names, then liquefying that person’s existing stock holding and using the proceeds to buy share in the microcap. They then wire the money to either an offshore account or through a series of straw men or dummy corporations.

“The number of these attacks on investors continues to rise as identity thieves increasingly target the securities industry,” said Joseph Borg, NASAA president and Director of the Alabama Securities Commission. “Investors need to carefully guard their financial information and continuously monitor their online brokerage records to ensure that they are not subject to this type of fraud.”

“As investors become increasingly comfortable with the ease and sophistication of services offered by online brokerages, we want to make sure that they remember not to let their guard down when they boot up their computers,” Borg said. “If you believe that funds have been transferred out of your account, notify your financial professional, preferably in writing and notify your state or provincial securities regulator.”