There is a tremendous amount of uncertainty regarding the federal regulation of bitcoin miners and other bitcoin related businesses. In particular, there is some worry that bitcoin miners could be categorized as Money Service Businesses, and therefore subject to the strict regulatory oversight of FinCEN.
Foruntately, it appears that FinCEN is leaning away from categorizing bitcoin minders as MSBs. In a recent private letter ruling, FinCEN seemed to indicate that mining bitcoins for yourself does not constitute a Money Service Business. Specifically, FinCEN stated:
“In undertaking such a conversion transaction, the user is not acting as an exchanger, notwithstanding the fact that the user is accepting a real currency or another convertible virtual currency and transmitting Bitcoin, so long as the user is undertaking the transaction solely for the user’s own purposes and not as a business service performed for the benefit of another. A user’s conversion of Bitcoin into a real currency or another convertible virtual currency, therefore, does not in and of itself make the user a money transmitter.”
This should put most bitcoin miners at ease about the possibility of being treated as a Money Service Business. It is less clear if mining pools or services like Cloud Hashing. In any case, this does not constitute a formal opinion by FinCEN, so it could change its stance in the future.