My wife received an inherited IRA last year, so took an RMD (required minimum distribution) last year (still under the pre Secure Act rules, thought that doesn't really matter).
We got a 1099R for the distribution, it had a Gross Distibution and Taxable amount 1 and 2a with an amount, say $17,000,000. (JK). But then I notice now it also has Box 2b Checked - Taxable amount not determined. Looking at the investment account (at Schwab), I notice the inherited IRA reports a basis for all the investments still there.
So, was the RMD my wife took not all taxable? How do we figure/decide the basis for the distribution, and do we have to fill out some Form 8606 to report the taxable amount?