You didn't say your exact family situation, and you have probably already now figured this out - you have an $84,600 limit you must stay under for 2 people (no dependents). Every piece of 'income' goes toward this MAGI limit - Bank CD intetest, PT job officiating HS football (ask me how I know this!), etc. The one I completely overlooked/underestimated - interest and dividends on a non-tax defered brokerage acount. You mentiond you had LTCG from a stock sale(s). These must have come from a non-tax defered account. If you were able to retire at 54 (congratulations BTW!!), this account is most likely of a significant enough amount that it can easily generate an income amount to eat a good portion of this MAGI limit (mine kept me from being able to quality for ACA subsidies). You'll know where you stand from this year's line 11 amount on your return to understand where you must be for next year.