Until recently, banks watched from the sidelines with envy as stablecoin market leader Tether Holdings boasted of billions in profits. Now they want in.Earlier this year, Societe Generale - Forge made its Euro-backed stablecoin — which basically represents fiat on a blockchain ledger — available to retail investors. Financial group Oddo BHF SCA is also working on a Euro-denominated one, and London-based Revolut is considering issuing its own version. AllUnity, a venture involving Deutsche-Bank o...