Why High-Net-Worth Investors Outgrow the Model Portfolio

There is nothing wrong with a model portfolio. It answers a real question — given this tolerance for risk, what mix of assets makes sense? — and the discipline it imposes is worth more than most of what passes for sophistication. The problem is not that the model is wrong. It is that it answers a question you may have already outgrown.

A model portfolio is built to a risk profile. It is not built to a tax return, an estate plan, a concentrated stock position, a trust with its own tax identity, or a charitable intention that arrives in a particular year. Once those are all true at once, much of what you actually keep turns on how holdings are arranged across accounts, when gains are recognized, and which lots are sold — none of which the model can see.

The spread that drives everything

Start with the arithmetic that makes the rest of it matter. In 2026, a married couple filing jointly reaches the top 37% federal bracket at $768,700 of taxable income. The 20% long-term capital gains rate applies to taxable income above $613,700 — a different and lower breakpoint. Layered on top of both is the 3.8% net investment income tax, which applies once modified AGI exceeds $250,000 for a joint filer.

So the top federal rate on bond interest and short-term gains is 40.8%; on long-term gains and qualified dividends, 23.8%. Seventeen percentage points separate them, and the gap turns on what kind of income a holding produces and how long you have held it — not on the manager who runs it.

Worth noting: that $250,000 threshold has never been indexed for inflation since it took effect in 2013, and the $3,000 annual limit on deducting net capital losses against ordinary income has been fixed in nominal dollars since 1978. Each year, rules written for a narrower group reach further.

Location before selection

The most underused decision in taxable wealth management is asset location — which account holds which asset.

The following is a hypothetical illustration, not a client account or a projection of results. Consider a married couple with $5 million at a 60/40 target — $3 million in equities, $2 million in bonds — held across a $3.5 million taxable account and a $1.5 million traditional IRA. Assume a 4.0% yield on the bonds, a 1.8% qualified dividend yield on the equities, and top-bracket federal rates, excluding state taxes and transaction costs.

A model implemented account by account mirrors the same 60/40 mix in both. The taxable account then holds $1.4 million of bonds throwing off $56,000 of interest taxed at 40.8%, plus $2.1 million of equities producing $37,800 of qualified dividends taxed at 23.8% — roughly $31,800 of current-year federal tax.

Now change nothing about the allocation — the household still owns exactly $3 million of equities and $2 million of bonds — and put the bonds where they are sheltered. The IRA holds $1.5 million of bonds; the taxable account holds $3 million of equities and the remaining $500,000 of bonds. Current-year federal tax: roughly $21,000 — about $10,800 less, from a decision that did not change the household's pre-tax allocation.

Two things that figure is not. It is not a return, and it is not free. Tax deferred inside the IRA is eventually paid at ordinary rates on withdrawal, so the lifetime benefit is smaller than a first-year snapshot suggests: Vanguard, modeling this over full horizons and net of that eventual tax, finds asset location worth up to about 0.3% annually, with its two illustrative investors landing at 6.1 and 13.3 basis points. Nor is the change risk-neutral — concentrating equities in the taxable account shifts the household's after-tax equity exposure, its liquidity, and where future rebalancing triggers tax. Vanguard also notes that for an investor holding only tax-advantaged accounts, asset location creates no tax advantage at all, because taxation is determined at the account level.

A model portfolio cannot make this decision, because it does not know how your wealth is divided.

Losses are an asset, and the rules are unforgiving

Realized losses offset realized gains, and up to $3,000 a year of the excess offsets ordinary income ($1,500 if married filing separately), with the remainder carrying forward for the rest of your life. Note that last part: unused carryforwards expire at death. They pass to no one — which is itself a reason not to defer every realization indefinitely.

Published estimates of what systematic harvesting is worth vary widely, and the range matters more than the headline. Chaudhuri, Burnham and Lo, in the Financial Analysts Journal in 2020, found a before-cost tax alpha of 1.08% a year over a 1926–2018 sample, falling to 0.82% once the wash sale rule was enforced. Vanguard's 2024 research reports median fifteen-year harvesting alpha of 0.47% to 1.27% across four wealth cohorts under skilled implementation, and 0.04% to 0.13% under poor implementation — measured on taxable equity assets only. In Vanguard's own case study, 0.47% becomes roughly 12 basis points at the total-portfolio level once taxable equities are a quarter of household assets.

The rules are where good intentions go wrong:

• The wash sale window is 61 days — thirty days before a loss sale through thirty days after. Repurchase a substantially identical security inside it and the loss is disallowed, then added to the basis of the replacement shares.
• A purchase inside your IRA triggers it too. Under Revenue Ruling 2008-5, if your traditional or Roth IRA buys the substantially identical security, the loss is disallowed and there is no basis adjustment. The loss is not deferred. It is gone permanently.
• Your spouse's purchase counts as your own for this purpose.
• Lot identification is a deadline, not a preference. Specific identification must reach your broker no later than settlement (the broker's written confirmation may follow within a reasonable time). Miss it and your broker's default method governs — generally first-in, first-out for stock, though average cost may apply to mutual fund and reinvested shares.

Some gains should never be realized

The most tax-efficient gain is one you never recognize.

Appreciated securities held until death generally receive a step-up in basis to fair market value, and the embedded gain disappears for income tax purposes. Not so a traditional IRA or 401(k), which passes to heirs as income in respect of a decedent with no step-up at all. Two accounts that look alike on a statement can have opposite consequences for the next generation.

Appreciated stock is also the right currency for charitable giving. A gift of long-term appreciated securities to a public charity is generally deductible at fair market value, subject to a limit of 30% of your contribution base with a five-year carryforward, and publicly traded securities require no qualified appraisal at any size. Give the low-basis shares; keep the cash.

Two changes took effect for tax years beginning in 2026. Charitable deductions are now allowed only to the extent they exceed 0.5% of your contribution base, and a rewritten section 68 caps an itemized deduction's value at 35 cents on the dollar rather than 37 for filers well into the top bracket. Compared with selling stock and donating the proceeds, the gain you never recognize remains the entire incremental advantage of giving shares directly — but both changes shrink the deduction side, which alters the math on timing and bunching. For those over 70½, a qualified charitable distribution of up to $111,000 per person in 2026 remains available directly from an IRA, though donor-advised funds, private non-operating foundations, and supporting organizations are not eligible recipients.

What changes when someone is paying attention

None of this is exotic. It is coordination — the recognition that a household is one taxable entity with many accounts, not many portfolios that share a last name. It shows up in specific places. A non-grantor trust hits the 37% bracket on taxable income above $16,000 in 2026, and the 3.8% net investment income tax reaches its undistributed net investment income above roughly that same figure — which makes whether income is distributed a live annual question. Medicare surcharges run on a two-year lookback, so a gain realized this year sets a premium two years out. Vehicle choice matters too: Morningstar found that in 2024 roughly 78% of U.S. equity mutual funds distributed capital gains, against about 7% of U.S. equity ETFs — a distribution you owe tax on whether or not you sold anything.

Individually these are small numbers, and what any one is worth depends entirely on a household's facts. Vanguard itself calls asset location's contribution modest next to asset allocation. But modest decisions, made correctly and repeated annually, are the part of the outcome you can actually control.

If your wealth has outgrown the question a model portfolio was built to answer, the next conversation is not about which funds to own.