as far as I know:
The IRS has decided to deal with convertible cryptocurrencies as a property [Payment of tax on capital gains] That means when you make a purchase using Bitcoin, you have to record the amount, subtract the cost from the price and report the difference.
So I think you will only pay/report if you make a conversion not holding.
you can use this tool to calculate taxes:
https://www.bitcoin.tax
its better to move this topic into
legal