Mr. Mercer, a hedge-fund magnate, is reportedly the main donor to a network of four super-PACs all backing Senator Cruz. Within a few weeks of Cruz’s campaign launch on March 23, the pro-Cruz super-PACS, all containing the words “Keep the Promise,” had raised an eye-popping $31 million.
A recent profile in The New York Times described Mercer as a “reclusive Long Islander,” who shares with Cruz “a passion for unbridled markets, concerns about the Internal Revenue Service, and a skeptical view of climate change.” Mercer’s net worth is undisclosed. He is the co-CEO of the hedge fund Renaissance Technologies.