VeriFund is simply a fund that swings back and forth from VRC to BTC. It does not fall under US tax code as there is never any conversion to FIAT and thus is just one property trading for another.
If that's true, then Bittrex wouldn't have to pay any taxes under the US tax code either. Until they convert to fiat you mean. But something still seems to be missing as that would mean you could operate a non-fiat exchange and never report a profit until you exchange to fiat.