Goldman Sachs GroupAnd Morgan StanleySome former executives have joined a cryptocurrency trading platform created by their peers, and a growing number of Wall Street veterans are betting on the volatile world of digital assets.

Amber Group appointed Dimitrios Kavvathas, a former partner of Goldman Sachs Group, as Chief Strategy Officer, and Todd Miller, former Managing Director of Morgan Stanley, as Chief operating Officer for America. Sotirios Kavvathas, who once held leadership positions at audit firms BDO and Royal Bank of Scotland, will be in charge of European operations, the Hong Kong start-up said in a statement on Friday. In addition, Amber has added three European directors, all from the financial industry.

Founded by five Morgan Stanley traders in 2018, Amber is one of many start-ups developing financial services for professional cryptocurrency traders and investors, ranging from over-the-counter trading to derivatives and structured products. In June, the company raised $100m from investors including DCM Ventures and Tiger Global Management, raising its valuation to $1 billion.

In June, co-founder Michael Wu said in an interview that the company manages about $1.5 billion in trading funds and expects revenue to grow tenfold to $500m this year.