Hi,
In 2018, I switched jobs and, due to a bonus paycheck I received right before quitting my first job, I already maxed out my 401k at my first job. My 2nd job, which started mid-2018, continued to contribute to my 401k and I had an overcontribution in that year. I had also rolled over my 401k at my previous job into my new 401k, so all those funds ended up co-mingled.
I noticed this in Feb 2019, and in March 2019 my 401k administrator issued me a corrective distribution. At the time, my current employer refused to issue me an amended W2 and told me that the 401k administrator would be the one to give me a tax document.
Fast forward to today (2020), and I have received my 1099-R code P. Box 1 (Gross distribution) reflects the full amount of the overcontribution to the 401k in 2018. Box 2a (taxable amount), however, shows a lower number. I understand that gains/losses on the overcontribution amount are supposed to be taxable in the year of corrective distribution, but I'm wondering where I find that number (my inference is that is it Box 2a minus Box 1, but I am not sure). Also, I am wondering how I should be reflecting the overcontribution as income in my 2018 taxes now that I have received this 1099-R code P.
Thank you so much for the help!
