A 1099-R for a Traditional IRA cannot have a blank box 2a. Traditional IRA'a 1099-R'a are required to have the same amount in box 2a that is in box 1 and also have the box 2b (taxable amount not determined) checked and the IRA/SEP/SIMPLE box checked. That combination allows the taxable amount to be modified if there is a non-deductible basis on an attached 8606 form.
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/i1099r_18.pdf">https://www.irs.gov/pub/irs-pdf/i1099r_18.pdf</a> ... 12
401(k)'s rolled into an IRA, if a direct rollover, will always have box 2a a 0 (zero) unless it is a Designated Roth direct rollover, then box 2a must be calculated by the administrator, but is usually the same as box 1.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
