More than three years after a report that Goldman Sachs ([[GS]] -0.2%) was assembling a crypto trading desk, the Wall Street stalwart has started trading two types of bitcoin-linked derivatives, CNBC reports, citing an internal memo.The new desk is part of Goldman's global currencies and emerging markets trading division, reporting to partner Rajesh Venkataramani, CNBC said.Last year, Goldman, in a slideshow to investors, said cryptocurrencies, such as bitcoin, "are not an asset class."The new crypto trading desk comes after the bank said in March it will offer its private wealth management clients access to digital assets.Goldman has been considering trading crypto for years. In late 2017, Bloomberg reported that the bank was forming a crypto trading desk, but then in September 2018, Business Insider said those plans were shelved.