Openbank, the fully digital arm of Spain’s Santander Group, has launched digital assets trading for retail clients in Germany. The move is a big step for one of Europe’s largest financial institutions into the digital asset space, with Spain to follow in the coming weeks. The new service allows Openbank customers to buy, sell, and hold bitcoin, as well as four top altcoins — Ethereum, Litecoin, Polygon, and Cardano — directly on the bank’s investment platform. The service sits alongside Openbank’s traditional investment products such as stocks, funds, ETFs, and robo-advisory services. By trading within its own platform, Openbank eliminates …