"181 days after the IPO date, or March 18, 2015. That’s when 429 million shares are available for sale in the public market, which is more than the 320 million shares the company sold in the IPO and about 17% of the shares outstanding.
But the biggest lock-up expiration date comes 366 days after the IPO, or Sept. 20, 2015, when 1.6 billion shares are allowed to be sold. That is 64% of the shares outstanding."