The joint-return bracket design creates marriage penalties for higher earners

Evidence

The 25 percent bracket hits singles with incomes between 37,650 and 91,150 and married couples with incomes between 75,300 and 151,900. Notice that the 25 percent bracket starts with married income at twice the level of single income (75,300 is twice 37,650), but it doesn’t end at that level (151,900 is less than twice 91,150). The marriage penalties begin with income taxed at the 25 percent bracket. — Dorothy A. Brown, The Whiteness of Wealth, 642

Categorization

• ADDENDUM: The tax-bracket marriage penalty mechanism pairs with the immodesty/sumptuary frame — here marriage itself shifts tax burden by income tier.