What Is the Tax Torpedo?

The tax torpedo is one of the most counterintuitive tax traps in retirement planning. It occurs when a retiree's income rises just enough to trigger taxation on Social Security benefits — causing a stretch of income where each additional dollar of withdrawal from a traditional IRA or 401(k) generates a combined effective marginal tax rate far higher than the nominal bracket rate would suggest. In severe cases, the effective rate on a marginal dollar of income can reach 40%, 46%, or even higher — even for retirees in the 22% or 24% federal bracket.

Understanding the tax torpedo requires understanding how Social Security benefits are taxed, why the interaction with retirement account withdrawals creates a non-linear effective rate, and what planning tools exist to defuse it before it fires.

How Social Security Benefits Are Taxed

Social Security benefits are not automatically taxable. Whether they are taxed — and how much — depends on a measure called combined income (also referred to as provisional income):

Combined Income = AGI + Tax-Exempt Interest + ½ of Social Security Benefits

The IRS compares this combined income figure to two statutory thresholds that have been fixed since 1984 and are not adjusted for inflation:

Single filers:

• Combined income below $25,000: 0% of benefits taxable
• Combined income $25,000–$34,000: up to 50% of benefits taxable
• Combined income above $34,000: up to 85% of benefits taxable

Married filing jointly:

• Combined income below $32,000: 0% of benefits taxable
• Combined income $32,000–$44,000: up to 50% of benefits taxable
• Combined income above $44,000: up to 85% of benefits taxable

The maximum taxable portion of Social Security benefits is 85% — no matter how high income climbs, at least 15% of benefits remain permanently tax-free.

These thresholds have never been indexed for inflation. A couple with $32,000 in combined income in 1984 was a middle-income household. In 2026, $32,000 in combined income is well within reach for many retirees simply from modest Social Security benefits plus small IRA withdrawals. The practical result: a steadily growing share of retirees pay tax on their Social Security benefits each year, even without any deliberate planning failure.

Why the Torpedo Fires: The Effective Rate Multiplication

The tax torpedo occurs in the income band where Social Security benefits transition from untaxed to taxed. Here is the mechanism:

In the 50% inclusion zone (between the lower and upper thresholds), each additional $1 of income from a traditional IRA withdrawal adds $1.50 to taxable income — the $1 itself, plus $0.50 of additional Social Security benefits that become taxable as a result. At a 22% marginal bracket, the effective rate on that dollar is 22% × 1.5 = 33%.

In the 85% inclusion zone (above the upper threshold), each additional $1 of income adds $1.85 to taxable income — the $1 itself, plus $0.85 of additional Social Security benefits now taxable. At a 22% bracket: 22% × 1.85 = 40.7%.

A retiree who crosses both thresholds in a single year — starting with income below $32,000 (MFJ) and ending above $44,000 — passes through the entire torpedo zone in one tax year. The effective marginal rate spikes, then returns to the nominal rate once 85% of benefits are fully included and no additional benefits can become taxable.

This is why the phenomenon is called a "torpedo" — the spike in effective rates is localized, not spread across all income. It fires in a specific income band and then ends.

A Concrete Example

A married couple filing jointly receives $36,000 in Social Security benefits annually. Their combined income from other sources — small pension, dividends — sits at $20,000. Their combined income is $20,000 + $18,000 (½ of $36,000) = $38,000, which puts them in the 50% inclusion zone. Currently $3,000 of their benefits are taxable ($38,000 − $32,000 = $6,000 × 50%).

They need $15,000 from their traditional IRA to cover expenses. They consider taking it all at once. Adding $15,000 moves their combined income from $38,000 to $53,000 — well above the $44,000 upper threshold. The full $15,000 IRA withdrawal is in play, but it drags additional Social Security into taxable income along the way.

The result: what looks like a $15,000 ordinary income addition at 22% is actually generating closer to $12,750 in additional taxable income from Social Security benefits becoming taxable — meaning the couple is taxed on roughly $27,750 rather than $15,000 of incremental income. The effective rate on the IRA withdrawal approaches 40%.

Had they instead spread the withdrawal across two tax years — taking $7,500 each year and staying within the torpedo zone rather than blasting through it — they would have paid significantly less total tax on the same dollars.

What Triggers the Tax Torpedo in Practice

Any income that raises combined income through the threshold bands can trigger or worsen the torpedo. The most common triggers for tech workers in retirement:

Traditional IRA and 401(k) withdrawals. Every dollar withdrawn from a pre-tax account counts toward combined income. For retirees with large traditional account balances — common among long-tenured tech workers who maximized 401(k) contributions for decades — the first years of RMDs can be substantial.

Required Minimum Distributions (RMDs). RMDs are mandatory withdrawals from traditional IRAs, 401(k)s, and most other pre-tax retirement accounts beginning at age 73 (for those born 1951–1959) or age 75 (for those born 1960 or later, under SECURE 2.0). The RMD is calculated by dividing the prior December 31 account balance by an IRS life expectancy factor from the Uniform Lifetime Table. At age 73, the factor is 26.5 — meaning an RMD of approximately 3.77% of the account balance. At age 80, the factor shrinks to 20.2, pushing the RMD to nearly 5% of the balance. As balances grow and factors shrink, RMDs often increase each year — potentially pushing more Social Security benefits into taxable territory whether the retiree wants the income or not.

Capital gains distributions. Long-term capital gains from taxable brokerage accounts count as AGI and flow into combined income. Even if taxed at 0% federal rate (because income is otherwise low), they still count toward the Social Security combined income calculation. A $20,000 capital gain that costs zero in capital gains tax can still trigger taxation of Social Security benefits — an indirect tax cost that the 0% rate conceals.

Tax-exempt interest. Municipal bond interest is explicitly included in the combined income formula, even though it is excluded from regular taxable income. A retiree holding a large municipal bond portfolio to minimize taxes may be inadvertently increasing combined income and triggering Social Security taxation.

Roth conversions. The income recognized in a Roth conversion counts toward combined income. A large Roth conversion in a year when Social Security benefits are already partially taxable can accelerate the torpedo effect significantly. However, a well-timed Roth conversion strategy — executed before Social Security begins or in low-income years — is also one of the primary tools for defusing the torpedo over the long term.

The RMD Connection: Why Tech Workers Are Particularly Exposed

Many FAANG and tech industry employees spend 20–30 years maximizing 401(k) contributions, often including employer matches that built large pre-tax balances. A senior engineer who contributed $20,000–$23,000 annually for 25 years into a 401(k) growing at 8% per year accumulates approximately $1,500,000–$2,000,000 in pre-tax assets by retirement — before employer match.

At age 73, the RMD on a $1,500,000 traditional IRA balance is approximately $56,600 (at factor 26.5). At age 80, the same balance — if it continued to grow — might generate an RMD of $75,000 or more. These mandatory withdrawals are on top of Social Security benefits, any pension income, dividends from taxable accounts, and other sources.

For this retiree, a $56,600 RMD on top of $36,000 in Social Security benefits and other income almost certainly pushes combined income well above the $44,000 MFJ threshold — meaning 85% of Social Security benefits become taxable, and the effective rate on every dollar of that RMD is amplified by the torpedo effect. Unlike voluntary withdrawals, RMDs cannot be skipped or reduced. The only way to address this problem is to reduce the pre-tax balance before RMDs begin — which is where Roth conversion strategy becomes critical.

See Required Minimum Distributions (RMDs) for a full treatment of RMD mechanics, tables, and planning considerations.

Strategies for Defusing the Tax Torpedo

The tax torpedo is not inevitable. The core insight is that it is better to pay moderate taxes on retirement income now — at known rates, in controlled amounts — than to be forced to pay elevated effective rates later when RMDs are mandatory and Social Security benefits are already in payment.

Roth conversions before RMDs begin. The most powerful tool for defusing the torpedo is converting traditional IRA or 401(k) balances to Roth accounts during the years between retirement and age 73 (or 75). These early retirement years often have lower income than peak working years — and lower income than the RMD years ahead. Converting pre-tax balances to Roth at, say, a 22% effective rate eliminates future RMDs on those converted dollars, reduces future combined income, and potentially keeps Social Security benefits entirely outside the torpedo zone. The optimal conversion amount each year is typically the amount that fills the current tax bracket without triggering the next marginal rate spike — requiring careful modeling. See Roth Conversions for mechanics and strategy.

Qualified Charitable Distributions (QCDs). A QCD allows IRA owners age 70½ or older to transfer up to $111,000 directly from a traditional IRA to a qualifying charity — excluding that amount from AGI entirely. Because a QCD never enters AGI, it does not count toward combined income. For a retiree with charitable intent, a QCD is more tax-efficient than taking the RMD as income and then donating cash: the QCD satisfies the RMD obligation without raising combined income, directly reducing Social Security taxation. The QCD limit is indexed for inflation annually ($108,000 in 2025, $111,000 in 2026). Additionally, up to $55,000 of the annual QCD limit can be used for a one-time transfer to a Charitable Remainder Trust (CRT) or Charitable Gift Annuity (CGA) — allowing a retiree to fund a lifetime income stream with pre-tax IRA dollars while satisfying part of the RMD tax-free.

Timing and smoothing withdrawals. For retirees with discretion over the timing of voluntary withdrawals (beyond mandatory RMDs), smoothing income across years to avoid large spikes through the torpedo zone reduces total lifetime tax. Taking somewhat larger withdrawals in years before Social Security begins — when combined income is lower — and smaller withdrawals later when RMDs and Social Security stack together is a basic but effective approach.

Roth IRA withdrawals during torpedo years. Once the torpedo zone arrives, Roth IRA withdrawals are the cleanest source of income. Qualified Roth distributions are tax-free, do not count as AGI, and do not count toward combined income. A retiree who has built meaningful Roth balances — through decades of Roth 401(k) contributions, Roth conversions, or both — can cover expenses in high-income years from Roth accounts without worsening Social Security taxation.

The Senior Bonus Deduction (2025–2028). The One Big Beautiful Bill Act, signed July 4, 2025, created a temporary additional standard deduction of $6,000 per qualifying individual (or $12,000 for MFJ) for taxpayers age 65 and older. This deduction reduces taxable income — which can in turn reduce the combined income calculation and keep retirees below or within the Social Security taxation thresholds. The deduction phases out for MAGI above $75,000 (single) or $150,000 (MFJ), at a rate of $0.06 per dollar of excess income, and disappears entirely at $175,000 (single) or $250,000 (MFJ). For tech workers with large RMDs, the torpedo zone itself may push MAGI above the phase-out threshold — meaning the deduction shrinks precisely when it would be most useful. The deduction is currently set to expire after 2028. For the four years it is in effect, it represents a meaningful planning variable for retirees near the torpedo thresholds.

The Tax Torpedo and NIIT

For tech workers retiring with substantial investment portfolios, the Net Investment Income Tax (NIIT) adds a third layer on top of the ordinary income rate and the Social Security torpedo effect. The NIIT is a 3.8% surtax on net investment income for individuals with MAGI above $200,000 (single) or $250,000 (MFJ). Unlike Social Security thresholds, the NIIT threshold does not adjust for inflation either — and it applies in addition to the torpedo effect, not instead of it.

A retiree whose income is in the torpedo zone and who also crosses the NIIT threshold faces an effective marginal rate that combines: the nominal bracket rate × 1.85 (torpedo multiplier) + 3.8% (NIIT). The result can exceed 50% on a marginal dollar of income in extreme cases. See Net Investment Income Tax (NIIT) for a full treatment.