https://www.bloomberg.com/news/articles/2018-04-16/barclays-is-said-to-be-sounding-out-clients-about-trading-crypto
The CME and CBoE futures markets were only the start which allows major institutions to hedge their positions. I really see this opening up a path to a major inflow of fresh money.
We had similar rumours about Goldman Sachs starting a cryptocurrency desk, but that went nowhere. Established banks have a huge reputation risk associated with cryptocurrency desks. Would you trust someone with your money if they lost a huge amount of money in crypto trading? Regulators won't look too kindly at such businesses as well.
It seems that the rumor about Goldman Sachs is not a rumor anymore. However, they will trade bitcoin futures and other derivatives first. Actual bitcoin trading will be there later. They will become the first Wall Street bank to open a cryptocurrency trading desk.
http://fortune.com/2018/05/02/goldman-sachs-cryptocurrency-trading-desk/