Mary-Kate Olsen is leaving NYU, according to published reports. According to her publicist, Olsen is taking an approved leave of absence from New York University so she can concentrate on business matters. Olsen's twin sister Ashley, also co-president of their company Dualstar, will remain at NYU.

Olsen's publicist tells People magazine that Mary-Kate's health is not a factor in her decision to leave school. The summer before classes began, Mary-Kate checked into the Cirque Lodge rehab facility in Sundance, Utah, for treatment of an eating disorder. The twins began attending NYU in September 2004. At the time, they purchased a $7.3 million penthouse in the trendy West Village, but they never moved into the apartment. Mary-Kate and Ashley Olsen are co-presidents of Dualstar Entertainment Group, a multimillion-dollar brand catering to young girls with home videos, CDs, books, apparel, fragrances and dolls. Fortune magazine last year estimated they were worth $137 million each.

Recently the 19-year-old twins bought out their business partner, took over the co-presidency of the business, hired a new CEO and expanded the company in new directions - including partnering with a boys clothing line.