Losing a spouse is devastating, but the financial shock of higher taxes can compound the grief. Known as the 'widow's penalty,' the tax code can hit surviving spouses with increased taxes, higher Medicare premiums, and more Social Security tax, even if their income drops.

When a spouse dies, the surviving partner's filing status typically reverts from married filing jointly to single. This triggers a lower standard deduction and compressed tax brackets, leading to a higher taxable income. Women are disproportionately affected, as they live on average five years longer than men, according to Katie Carlson, head of wealth strategy at Bank of America Private Bank.

Consider a couple with $100,000 in taxable income. As joint filers, they fall into the 12% bracket. But a widow with the same income moves into the 22% bracket. Additionally, higher taxable income can trigger Medicare's income-related monthly adjustment amount (IRMAA) two years later, costing nearly $1,150 more annually. Social Security benefits also become more taxable: a single filer needs just over $34,000 in combined income to have 85% of their benefit taxed, compared to $44,000 for joint filers.

Early planning is crucial. Patrick Simasko, an elder law attorney, advises maximizing withdrawals in the year of death while still benefiting from the joint rate. A qualifying surviving spouse (QSS) with a dependent child can file jointly for two more years. Other strategies include Roth conversions, shifting to tax-efficient investments like ETFs, and using qualified charitable distributions (QCDs) from retirement accounts after age 70½ to reduce taxable income.