The $40,000 Tax Move That Comes After Your 401(k) Hits Its Limit

A 58-year-old engineer in Palo Alto, married filing jointly, earns $750,000 a year, has already stuffed $4 million into 401(k)s and IRAs, and parks another $1.2 million in a brokerage account that holds a single S&P 500 fund. The 401(k) is maxed. The mega backdoor Roth is maxed. The next tax dollar saved has to come from somewhere else, and for households at this income level it almost always comes from the taxable account.

Direct indexing is how it gets done. Instead of owning the SPDR S&P 500 ETF (NYSEARCA:SPY), the investor holds 150 to 250 of the underlying constituents in a separately managed account that mirrors the index within a tight tracking band. The fund wrapper disappears. Every individual lot becomes a tax asset. The strategy has moved well beyond the ultra-wealthy: a July 2026 Forbes report noted that more than 21,000 stock trades President Trump disclosed for 2025 were apparently the result of direct indexing, underscoring how broadly the approach has spread.

Why the index can rise while a third of the names bleed

The S&P 500 has extended its gains through mid-2026, but that headline conceals substantial dispersion underneath. At various points in the first half of the year, Microsoft was down sharply from its year-end price, JPMorgan Chase softened, and Bank of America gave back ground as the 10Y-2Y spread stayed compressed and the Fed funds upper bound held near 4%. These are losses that exist inside the index but are invisible to the ETF holder. The fund nets them against winners and reports one number. The direct-indexed portfolio reports 500. The losers can be sold to the IRS while the index exposure stays intact.

The $40,000 figure, worked from the bottom up

In a normal-volatility year, 30% to 50% of S&P 500 names show losses at some point even when the index finishes flat or higher. Early 2026 was anything but normal. The VIX crossed 30 in March on geopolitical tension, then surged toward 60 in April as escalating tariff announcements triggered some of the largest single-day S&P 500 moves since 2020. Those spikes created harvesting windows across rate-sensitive financials, mega-cap tech, and industrials, even as the index eventually recovered its footing.

On a $1.2 million direct-indexed sleeve, that environment translates to roughly $30,000 to $50,000 of harvested losses per year in a volatile stretch. Call it $40,000 as a working figure. Applied against long-term capital gains at the 23.8% federal rate including NIIT, with the surplus $3,000 offsetting ordinary income at the 32% bracket, a single year of harvesting is worth $9,520 to $12,800 in current-year tax. Carried out over 15 years before any step-up in basis at death, the cumulative savings compound to $140,000 to $190,000.

Where this connects to Medicare and Roth conversions

Harvested losses lower realized capital gains, which lowers modified adjusted gross income, which lowers IRMAA exposure once the household crosses 63. For a 50-year-old today, this is the mechanic that opens runway for Roth conversions in the 60-to-63 window without tripping the two-year Medicare lookback. The conversion creates ordinary income. The harvested losses cannot offset it directly, but the suppressed capital gains keep the surcharge brackets clear of the conversion stack.

What to actually do

1. Price the fee drag honestly. Direct-indexing SMAs vary considerably in cost. Schwab and Fidelity both charge around 0.40%, while newer platforms like Wealthfront’s S&P 500 Direct run as low as 0.09%, compared with SPY’s 0.09% expense ratio. On $1.2 million, the incremental annual fee at the higher end runs $3,700 or more. If the harvest yields $9,500 or more in tax savings, the math works at that level. Below roughly $400,000 in a taxable account, the cost-benefit math generally does not pencil out regardless of platform.
2. Ask whether your current brokerage account can be transitioned in kind. Several platforms will migrate appreciated ETF lots into the SMA without triggering a sale, gradually unwinding the fund and building the constituent positions around it. Liquidating SPY outright on a position with embedded gains can wipe out years of harvest value in a single tax bill.
3. Coordinate the harvest calendar with concentrated stock events. RSU vests, ISO exercises, and a planned sale of a private business all create the realized gains that harvested losses are most valuable against. Pair them in the same tax year. Track wash-sale windows around dividend ex-dates as well, since a sale and a repurchase within 30 days can disallow the loss entirely.

The 401(k) is the foundation. The taxable account is where affluent households quietly add another decade of after-tax compounding, and direct indexing is the lever most of them never pull.

Editor’s note: This update corrects SPY’s expense ratio to 0.09% (from the original “roughly 0.1%”), refines the direct-indexing fee comparison to reflect the wide range across platforms, expands the VIX narrative to include the more severe April 2026 spike to near 60, and adds context about President Trump’s disclosed 2025 stock trades as a widely reported example of direct indexing in practice.

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