Mary Kate & Ashley Olsen

(Ethan James Green for WSJ. Magazine )

They started their careers as child actors, but the Olsen twins have become business moguls since their days as movie stars.

The pair founded their company, Dualstar in 1993 which produced movies, TV shows, video games and magazines.

In addition, the Olsen twins also launched their own accessorize line, The Row in 2006 as well as their fashion label, Elizabeth and James in 2007.