My new employer offers the Mega Backdoor Roth option. After-tax contributions can be automatically & immediately converted to Roth within the 401(k), and can be rolled over to a Roth IRA at any time. I just did the Roth 401(k) to Roth IRA rollover for the first time.
The 401(k) provider (Fidelity) sent me a paper "Distribution Statement" in the mail for this transaction, listing the amount that was transferred to my Roth IRA. Will I need to keep this for tax filing purposes, either when filing for this year or for when I eventually withdraw the funds from the Roth IRA? Or should the broker capture all the relevant information in an end-of-year tax form they will provide?