All were accused of illegal mutual fund trading.
The move was made a day after its former vice chairman pleaded guilty to concealing evidence of illegal mutual fund trading.
Jack White provides mutual fund trading through the Internet, also at a 10 percent discount.
Mr. Brown started investigating mutual fund trading last spring on a hunch and a tip.
Alliance suspended two other executives at the end of September for their roles in improper mutual fund trading.
The company said yesterday that it was cooperating with regulators and was continuing its own investigation into fund trading.
Some friends argue that late mutual fund trading, an open secret for years in the hedge fund business, was a gray area.
July 2008: Addition of analyst reports and online mutual fund trading.
Mr. Spitzer and other regulators have been investigating two types of fund trading.
Other companies under investigation for their role in improper fund trading have also said that their gains from such activities were small.