Billionaire investor Paul Singer gave $2.5 million to a super-PAC supporting Sen. Marco Rubio's (R-Fla.) presidential bid, according to documents sent to reporters by the group on Sunday. The contribution to Conservative Solutions came in late November, almost a month after it was reported that the hedge fund manager would be supporting Rubio. Singer is a longtime Republican donor and the founder of hedge fund Elliot Management Corporation. According to Forbes, he is worth $2.1 billion, making him the 327th-richest American. Filings from the super-PAC also showed that another hedge fund manager, Kenneth Griffin, head of investment firm Citadel, also...