The Marriage Penalty at the Top

The brackets are exactly doubled for joint filers up through 32%, and then they stop being. For 2026 the 35% bracket opens at $256,225 single and $512,450 MFJ — doubled, as expected — but the 37% bracket opens at $640,600 single and only $768,700 MFJ, which is 1.2 times, not two. Two people each earning $640,000 pay 35% on their top dollars while single and 37% on roughly $512,000 of combined income once married. That is the marriage penalty, and at this income level it is the only place it still exists in the rate schedule.

Several thresholds that are not indexed compound it. The NIIT and additional-Medicare thresholds are $200,000 single and $250,000 joint — 1.25 times, not two — so a dual-earner couple crosses into both surtaxes at a combined income two high earners would clear individually. The SALT phase-down threshold is the same for single and joint filers, meaning a married couple hits the 45.5% band described in section “Eligible Principal” at half the per-person income a single filer would need. None of this is avoidable by filing separately; the separate brackets are simply half the joint ones, which is where the penalty came from.