In the latest sign of digital currencies going mainstream, Silicon Valley’s most prominent startup incubator will allow its spring cohort of entrepreneurs to receive their funding in stablecoins. Y Combinator, whose alumni include the founders of Airbnb and DoorDash, announced on Tuesday that founders can opt to receive their customary allotment—typically around $500,000—in the Circle-issued USDC. Startup founders who choose stablecoins can choose to receive the tokens on various blockchains suc...