Why is ATVI worth $9 billion more today than on August 27st?

I sold a 9/28 call at 72.5 when it was trading at around $69 per share. Now it's at $81 per share? What changed in the last 15 days that has made ATVI so much more valuable?

Submitted September 13, 2018 at 08:27AM by Gorsuch2 https://ift.tt/2Mr5CzJ