Quote from: erk on January 07, 2018, 02:34:58 AM

Where, in US law, does it say that an exchange like Bittrex which doesn't deal in fiat, is classified as a "money transmitter" ?

The relevant laws are published here:
https://www.law.cornell.edu/cfr/text/31/1022.380
https://www.law.cornell.edu/cfr/text/31/1010.100

Quote

(5)Money transmitter -

(i)In general.

(A) A person that provides money transmission services. The term money transmission services means the acceptance of currency, funds, or other value that substitutes for currency from one person and the transmission of currency, funds, or other value that substitutes for currency to another location or person by any means. Any means includes, but is not limited to, through a financial agency or institution; a Federal Reserve Bank or other facility of one or more Federal Reserve Banks, the Board of Governors of the Federal Reserve System, or both; an electronic funds transfer network; or an informal value transfer system; or

(B) Any other person engaged in the transfer of funds.

If USDT isn't "value that substitutes for currency" then I don't know what is. According to Tether LTD, each USDT is backed by one USD held in reserve by Tether LTD, and may be redeemed as such. Further, the SEC has stated that their interpretation of the law is that cryptocurrency transactions should be treated as cash transactions. Bittrex allows deposit/withdrawal/exchange among different users in both a USD derivative and cryptocurrency. So, the bold sections seem to imply they are a money transmitter.

Clearly Bittrex's legal team believes they are a money services business, since they registered as one with FINCEN. That's an open admission that they feel required under the BSA (and related laws) to perform KYC among other AML requirements.

Whether or not you agree with their legal interpretation, that's why they require KYC.