Facebook founder and chief executive Mark Zuckerberg's sister is leaving the company as director of marketing according to AllThingsD.

Randi Zuckerberg, the older sister of Mark, has been with her brother for most of the way. She joined Facebook as Creative and Buzz Marketing back in 2005 and has been there ever since. In this six year period, Facebook has gone from a growing college-based phenomenon to the global leading social network with more than 500 million users worldwide.

According to her resignation later, which AllThingsD posted, Randi Zuckerberg is leaving to start her own firm. She won't leave Facebook behind completely. She said she will use the social network to help companies develop their programming in new and social ways. Her new company will be called RtoZ Media.

"Now is the perfect time for me to move outside of Facebook to build a company focused on the exciting trends underway in the media industry," Zuckerberg said in her resignation letter.

Randi Zuckerberg pointed to several partnerships with the media as part of what she was most proud of during her time at Facebook. She said launching Facebook Live, which culminated in a Town Hall with President Barack Obama, was one of these initiatives. She also appreciated various partnerships with media for election coverage both in 2008 and 2010.

According to AllThingsD, Facebook has confirmed the departure. Facebook did not respond a request for comment.

Like her brother, Randi Zuckerberg attended Harvard University. Unlike Mark, she graduated. Mark Zuckerberg famously dropped out of Harvard to start Facebook.