If you’ve held the same cryptocurrency from the beginning of the year to the end (i.e. bought it in previous tax year and haven’t disposed of it during current tax year), there are no tax consequences. Foreign currency held at year-end, are reviewed for fluctuations and value, with the difference of value accounted for as a capital gain or loss. However, since cryptocurrency is a commodity, there is no such review of cryptocurrency value held at year-end (regardless if there is fluctuation in underlying USD exchange rate).
Please be advised that NDAX does not provide any tax, legal or accounting advice. This material has been prepared for informational purposes only, and is not intended to provide, and should not be relied on for, tax, legal or accounting advice. You should consult your own tax, legal and accounting advisors before engaging in any transaction.