I opened a backdoor Roth IRA account last year (Dec 2019) with the Vanguard and forgot to realize that I also had a rollover IRA with the Fidelity. I recently found out that this is not allowed. I am in the process of converting the rollover IRA into my current 401K plan. I hope this should resolve the problem. However, I was told that I have to pay tax on the rollover IRA last year. How can file this? What form and calculation method should I use. Thanks.
M.
