No taxes owed.

Yeah its a bit confusing but this is typical "book" change vs "tax" change. This happen currently with other "mark to market" accounting entries, so its not unique.

What you do is also create a "deferred tax liability" entry for that gain. So if you show $1,000,000 "income gain", you create a $220,000 "deferred tax payment" as a liability.

Then when you finally sell, those amounts become realized (at whatever real price).