So you did a transfer or rollover from the 401K to the IRA? I assume it was to a Traditional IRA. When you take a distribution or withdrawal from a 401K or Traditional IRA it is taxed the year you take it as ordinary income at your tax rate.
You don't report it as a gain or loss. You don't have to worry about changes in value. The whole distribution is income. That's the benefit of IRAs, they grow tax deferred. But when you take it out it isn't taxed as capital gains just as regular income. If it goes down in value then you will be taking out less income to be taxed on.
You don't report any transactions, interest, dividends, gains or losses inside the IRA. Just distributions.
