updated 03/20/2000 AT 01:00 AM EST
•originally published 03/20/2000 AT 01:00 AM EST
Onscreen as well as off. In his best-known spot, wiseacre Stuart photocopies his face, then guides straitlaced boss "Mr. P" through his first online trade. Since the first of Maronna's two ads began airing last March, Ameritrade's accounts have increased by more than 60 percent. Though there are no plans for more Stuart commercials as yet, the public has spoken. "Even our competitors e-mailed us to say how much they like them," says company spokesman Pete Ricketts.
Maronna's mix of confidence and quirkiness caught the eye of director Dewey Nicks, who let the actor ad-lib his lines. "I loved his sarcasm," says Nicks. "It also helped that that haircut is his."
Though Nicks calls the actor and Stuart "interchangeable," there are some key differences. Maronna has never traded a stock online. He doesn't even own a computer. Moreover, in one ad, "Stuart has a blonde girlfriend," jokes the unattached Maronna, whose guidance counselor mom and firefighter dad (who died in 1998) supported their son's acting career since his debut in a commercial at age 5. He later played Macaulay Culkin's brother in 1990's Home Alone. But Maronna can't deny all comparisons to his alter ego. "Stuart's not afraid to make fun of people," he admits, "and neither am I."