Say a person turns 70 in July of 2026. That person has not yet started Social Security. The reason is because that person has been performing Roth IRA conversions and wanted to keep income low enough to not trigger IRMAA surcharges.
Can that person:
Continue to perform Roth IRA conversions throughout 2026,
Claim Social Security in a way to start receiving payments in January 2027 (6-months after turning age 70),
Use the 6-month look back rule to get Social Security payments in arrears for the six months from July to December 2026, and
Only count the Social Security income as income starting in 2027?
Yes, assuming that they time the request correctly so that they won’t get the lump sum until January, 2027. That could be an issue if they apply any time before the end of 2026 - but applying in 2027 could mean that they would lose a month of benefits, depending on how long it takes SS to process their application (like if there is a delay because of a government shutdown, for instance). The problem is - when applying for a lump sum of retroactive benefits, the timing of the lump sum payment may not always be exact.
I would just point out that for someone who went over the SS limit in all 35 of their highest earning years and delays claiming until age 70 has a maximum available benefit of $5,181/month in 2026. If they claim in July, 2026, that means their first check would come in August, 2026 - so they would get 5 checks in 2026, for a total of $25,905 That’s the maximum. And they would end up having to count that $25,905 in 2027 anyway, which would mean that they would have to reduce their 2027 Roth conversion by that extra amount.
Is it really worth the time and hassle to get that $25,905 converted a year early, when you will have to reduce the next year’s Roth conversion by that amount? Because even if we assume no increase in SS benefits from 2026 to 2027, their 2027 SS income will now be $88,077 instead of the $62,172 it would have been if they had just claimed when they turned 70. Depending on other income, that could push them into the first IRMAA bracket. And the first IRMAA bracket is likely to be more expensive in 2029 than it was in 2028.
(As always, YMMV - they would need to look at what their actual benefit is if they haven’t reached that maximum benefit level.)
To me, the juice wouldn’t be worth the squeeze. I would just plan for claiming SS in July 2026 (so my first check would come in August, 2026), and adjust my Roth conversions based on the assumption that I would have SS income in 2026.
Yeah — it’s more a hypothetical “what if” than an actual plan. Good to know that it’s in the realm of possible, but more likely to be an edge case than anything else.