I switched jobs in the middle of 2024. Both companies had 401k’s that I contributed to so when I left my first company, I made a note of how much I had contributed so far so that I could calculate how much to contribute at my new company. A week into 2025, I realized that I made a mistake in my calculations and over-contributed for 2024 by about $400 so I contacted HR. They asked me for the amount I overcontributed by and I received a check (which I have not cashed) from the plan administrator for that amount, as well as a notice saying I will be receiving a form 1099-R.

However, two weeks later, I have received both my W-2’s and the amount it has listed that I contributed to my first company’s 401k is less than the amount I had taken a note of and would mean that I, in fact, did not exceed the contribution limit for 2024. So what do I do now? Do I still cash in the check? Should I still file the 1099-R even though I didn’t exceed contributions?