It was a shocking bet even when it was made during bitcoin's sharp rise last year: $1 million that by the end of 2018, bitcoin would be worth more than $50,000. The bet, made by the crypto hedge fund BlockTower Capital, would have given the manager the chance to buy 275 bitcoins at $50,000 apiece — any time before December 28, 2018, a purchase that would have cost $13.8 million. The manager spent just under $1 million on those call options, which will expire this Friday.