Fanatics is buying its way deeper into prediction markets, striking a deal to acquire a federally regulated exchange and clearinghouse from brokerage giant BGC Group as sports-betting heavyweights race to stake out ground in the fast-growing sector. The sports platform said Monday it will purchase Water Street Labs, a CFTC-registered designated contract market, and CX Clearinghouse, a registered derivatives clearing organization, from Nasdaq-listed BGC. Terms weren't disclosed.