Will large one-time 401k deposit after brief work affect my Social Security benefits?

Not sure about 401k deposits specifically but when I worked part-time last year while on SS, I had to report ALL income regardless of where it ended up. The SSA looks at what you earn, not where you put it afterward. You should definitely call and ask them directly.

This could definitely trigger earnings test issues. For Social Security purposes, what matters is when the income is earned, not when it's paid or where it goes. Even though the money is going into your 401k, if it's compensation for work performed in 2025, it counts toward your earnings limit for this year. At age 67, you're at Full Retirement Age (FRA) so there's no earnings limit for you anymore! You can earn as much as you want without reduction in benefits. However, you'll still need to report the income for tax purposes, and it may cause a portion of your SS benefits to become taxable depending on your overall income level.

watch out!! my brother did somethin similar and SSA considered it DEFERRED COMPENSATION and counted it for the year he did the work NOT when it was deposited!!!! ended up having to pay back $4200 in benefits and didnt find out till NEXT YEAR when they did a review. major headache!!!

Several important points to consider here: 1. Since you're 67 and past Full Retirement Age (FRA), the earnings test no longer applies to you. You can earn any amount without reduction in your SS benefits. This is a key advantage of waiting until FRA to work. 2. However, the contribution itself needs proper classification. If this is truly compensation for current work (even if deferred), it would be reported on your W-2 and could potentially increase the taxation of your Social Security benefits. 3. There's a distinction between a regular 401(k) contribution (which has annual limits and must come from salary) versus an employer contribution (which has different rules). 4. If this is structured as an employer contribution rather than deferred compensation, the tax treatment might be more favorable. I'd recommend consulting with both a tax professional and having your employer specify exactly how they'll classify this payment to ensure proper reporting.

I had such a hard time reaching someone at SSA about a similar issue last month. Called for 3 days straight and kept getting disconnected or told the wait was over 2 hours. Finally found this service called Claimyr (claimyr.com) that got me through to an agent in about 15 minutes! They have a video showing how it works: https://youtu.be/Z-BRbJw3puU. Since you need specific answers about your situation, might be worth checking out instead of waiting on hold forever. My question was about working after starting benefits too, and I needed to speak with someone who could look at my specific record.

WAIT - this is a HUGE red flag to me!! Why would your former employer want to make such a large 401k deposit AFTER you do work for them?? This seems like they're trying to avoid paying employment taxes or something fishy. Normal companies would just pay you regular wages. BE CAREFUL and get everything in writing!!!

i think ur overthinking this lol... since ur over FRA u can make as much $ as u want. my dad works full time and gets his full SS check every month no problem

One thing nobody has mentioned yet - if this is classified as an employer contribution to your 401(k), it doesn't count against your personal contribution limit ($7,500 for 2025 if you're over 50, plus catch-up). Employer contributions have a much higher combined limit. That said, there are strict rules about how employer contributions work, especially for highly compensated employees or in situations where a company brings someone back for temporary work. I'd suggest having your former employer connect you with their benefits administrator who can explain exactly how this will be structured and reported.

whatever u decide DOCUMENT EVERYTHING!!! save emails texts everything about what they promised and how they said it would work. SSA can audit u years later and u need proof!!!

Just wanted to chime in as someone who went through a similar situation last year. I was 68 and took on some consulting work with a bonus that was structured as an employer 401k contribution. The key things I learned: 1) Since you're past FRA, no worries about earnings limits affecting your SS benefits, 2) Make sure you get clarity on whether this is deferred compensation (counts as income for the year you work) or an employer contribution (different tax treatment), and 3) The timing of the deposit matters less than when the income is considered "earned" by IRS standards. I ended up having my tax preparer review everything beforehand and it saved me from any surprises. The documentation advice from others here is spot on - keep everything in writing!