CHICAGO – Bitcoin's debut on a major U.S. exchange is a hit so far, with the price of the first-ever futures contract for the virtual currency rising 16 percent. The futures contract that expires in January was up $2,440 to $17,900 Monday afternoon on the Chicago Board Options Exchange. Trading began Sunday, and the price rose as high as $18,850, according to data from the CBOE. The CBOE futures don't involve actual bitcoin. They allow investors to make bets on the future direction of bitcoin.