A former Goldman Sachs banker plans to launch a digital currency platform that will make it easier for investors to short one cryptocurrency against another, potentially bringing the nascent market one step closer to the financial mainstream.

Alex Grebnev, who worked at Goldman Sachs for almost a decade in various roles in equities and derivatives structuring before joining Merrill Lynch, is working with an existing cryptocurrency exchange called Changelly. He plans to launch a platform for digital currencies later in 2018...