Billionaire investor Carl Icahn has Netflix Inc. NFLX, -0.05% to thank for being more than $100 million richer in one day. The most recent regulatory filing showed the his Icahn Associates hedge fund owed 1.4 million Netflix shares, or 2.3% of the shares outstanding, to make it the eighth largest shareholder of the video-streaming company. If his holdings remain the same, the $80.56, or 17% surge in Netflix's stock in Thursday afternoon trade after the company's first-quarter results, would mean Icahn is making $113.7 million on his investment in one day. Since Dec. 31--the stock is up 63% year to date--Icahn would have made $302.7 million. Meanwhile, Netflix's largest shareholder, Capital Research & Management Co., which owned 7.27 million shares as of Dec. 31, would be making $585.5 million today, and $1.56 billion this year.