Bitmex is the leading Bitcoin derivative trading Hong-Kong based exchange is closing the accounts of U.S residents after the investigation of CFTC ( the US Commodity Futures Trading Commission).
U.S residents are not allowed to open an account on Bitmex but many traders access Bitmex by using VPNs. After the investigation news spread among the public, people start withdrawing their funds from Bitmex.
There are rumours that Bitmex may freeze the funds of all users, but still, Bitmex is running and working fine for users (that region is not blocked).
After that, a series of tweets start from Bitmex traders across the globe that Bitmex may force users to do KYC for further services.
Recently Binance has announced to stop giving services in the United States. SEC has very strong laws against money laundering and any scam with US citizen.