She Made $50,000 Protecting Her Tech Stocks From an AI Crash. Now $20,400 of Her Annual Social Security Will Be Taxable

Wall Street spent late October buying protection against an AI selloff. Consider a hypothetical single retiree who got in early. She hedged her tech-heavy portfolio with stock options, closed the winning position for a $50,000 net taxable gain and kept her shares.

Her regular income is modest and steady: $24,000 a year from Social Security and $18,000 from a pension. The gain feels like a pure win. At tax time, it also changes how much of her Social Security counts as income, from $2,500 to $20,400.

A single good year in the market can create a tax surprise well beyond the investment gain itself. For retirees collecting Social Security, the difference can run into thousands of dollars.

How One Trade Pulled 85% of Her Benefits Into Taxable Income

The IRS uses a figure called combined income to decide how much of your Social Security is taxable. It equals one-half of your benefits plus all your other income, including tax-exempt interest. Before the trade, hers was $30,000: the pension plus $12,000, which is half her benefit.

Single filers face two lines. Above $25,000, up to 50% of benefits can become taxable. Above $34,000, up to 85% can. Those figures are written into the tax code as fixed dollar amounts with no inflation adjustment, so they catch more retirees every year.

The gain pushed her combined income to $80,000, well past the second line. Her taxable benefits hit $20,400, which is the ceiling: 85% of her benefits.

Her $50,000 gain added $67,900 to her income before deductions, because it brought another $17,900 of her Social Security into the taxable column.

The ceiling works in her favor from here. Once 85% of benefits are taxable, more income can’t make more of them taxable. If she closes another hedge later this year, that gain gets taxed by itself and pulls in no extra benefits.

What the $17,900 Jump Really Costs Her

That jump is added income, not another $17,900 in taxes. Her adjusted gross income (AGI) reaches about $88,400 before deductions. The 2026 standard deduction for single filers is $16,100, with additional deductions available to eligible people 65 and older.

The tax bill depends on those deductions and how the options are treated. Gains on ordinary stock options can be short-term or long-term, while some index options follow different rules. The $17,900 increase makes more of her benefits taxable, but it doesn’t all automatically get taxed at 22%.

Medicare is one thing she can stop worrying about for now. Her $88,400 income is below the current $109,000 threshold for higher Part B premiums. A bigger gain might have crossed it, adding at least $81.20 a month to her Medicare bill under the 2026 rates. Because Medicare looks at income from two years earlier, any surcharge tied to her 2026 gain would show up in 2028, when different income thresholds will apply.

Why Bunching Gains Into One Year Can Save Money

Splitting the gain into two $25,000 pieces would put 85% of her Social Security into taxable income in both years, assuming her pension and benefits stay the same. Taking the full $50,000 in one year hits that ceiling only once. That’s $17,900 less in taxable Social Security across the two years, although the overall tax savings depend on her deductions and tax brackets.

Two Moves Worth Making Before Year-End

1. Set aside the tax money now. A pension and Social Security often come with little or no tax withheld. You can ask Social Security to withhold tax using Form W-4V, or make an estimated payment using Form 1040-ES. Either one helps you avoid an underpayment penalty and a surprise bill in April.
2. Plan any other gains or IRA withdrawals with the full year in mind. If her income returns to its usual level next year, less of her Social Security will be taxable again.

Her result depends on her filing status, how long she held the options and whether any other deductions apply, and yours will too. Calculate your own numbers before you make the next trade.

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