What is Mr. Big's real name in the television series, "Sex and the City"?

The nickname "Big" refers to his status as a "major tycoon, major dreamboat, and majorly out of [Carrie's] league," according to the show's dialogue. (His real name is not revealed to viewers until the final episode of the series; in a running joke, whenever Carrie is about to introduce Mr. Big to another character onscreen, she is interrupted before she can say his name.)