More than six million current and former customers of online brokerage TD Ameritrade Holding will be able to benefit from the settlement of a class-action lawsuit filed over the theft of client contact information.

Formal notice of a settlement agreement will be sent to people who used TD Ameritrade's services before mid-September 2007.

U.S. District Judge Vaughn Walker in San Francisco approved a revised version of the settlement agreement earlier this month despite some misgivings about it. Last summer, Walker rejected an earlier version of the deal.

Anyone who held an Ameritrade account or provided an e-mail address to the company before September 14, 2007, could benefit from the lawsuit. The database that was breached included information on 6.2 million people.

TD Ameritrade is 40 per cent owned by Toronto-based TD Bank.

The plaintiffs in the lawsuit said they received unwanted e-mail ads about certain stocks. The ads appeared to be designed to manipulate the value of thinly traded stocks.

Ameritrade officials and one of the lead plaintiff's attorneys, Scott Kamber, have said the data theft has not been linked to cases of identity theft.

As part of the proposed settlement, the Omaha-based company will pay nearly $1.9 million in legal fees and cover the cost of one year of anti-spam service for the victims. Ameritrade also promised to better protect customer data.