IRS Form 8606 is typically filed to report activity of nontaxable assets in your IRA.
For example, Form 8606 is required, if any of the following occurred during the last year:
If you made a contribution to your traditional IRA, and you claimed a tax deduction for all or a portion of it.
You had after-tax amounts in your IRA from IRA contributions for which you did not claim a deduction, or rollovers of after-tax amounts from your 401(k) or 403(b) plan, and you took a distribution from any of your traditional IRA, SEP IRA or SIMPLE IRA.
You converted amounts from your traditional IRA, SEP IRA or SIMPLE IRA, unless the entire amount was recharacterized (reversed).
You received a distribution from your Roth IRA.