Bitcoin課税の新論文がでていた

Rethinking Basis in the Age of Virtual Currencies
Adam Chodorow

In Notice 2014-21, the IRS announced that virtual currencies
like Bitcoin would be treated as property—and not foreign
currency—for income tax purposes. As a result, taxpayers may owe
tax each time they sell or spend such currency. The IRS also declared
that the traditional “stand-alone” basis rules would apply to virtual
currency. This decision permits taxpayers to manipulate their tax
liability by picking and choosing which virtual coins to dispose of. In
this Article, I argue that taxpayers should be required to pool the
basis of their virtual currency to ensure that tax gains and losses
match realized economic gains and losses.

Over the years, politicians of both stripes have proposed pooling
basis for securities and inventory, to no avail. The rise of virtual
currencies offers a rare opportunity to re-examine the basis rules for
such assets. Allowing taxpayers to manipulate their tax results
without changing their economic gains or losses undermines the tax
system and permits taxpayers to take advantage of the time value of
money to reduce their real-world taxes. In the second half of this
article, I argue that either Congress or the IRS, exercising its
regulatory authority, should require taxpayers to pool basis for a
wide variety of fungible assets, including securities and inventory.