How does Ackman get so many shares to short for so long in $HLF?

I heard in a internview w/ Ackman that he has a 1 Billion+ short position in Herbalife.

My question, where does he get all these shares to short for this long without getting a buy in or something? Or is he just shorting Icahn's longs? lol

Thank you!!

Submitted February 27, 2015 at 10:02PM by xSimoHayha http://ift.tt/18wmMIN