Four Doors Out of a Concentrated Position: What Each One Actually Costs

I spent nearly twenty years inside institutional asset management, and the most expensive question I ever watched people get wrong wasn't about picking investments. It was this one: "I have most of my net worth in one stock. How do I get out without losing a third of it to taxes?"

The honest answer is that there are four doors out of that room, and every one of them has a price on it. The price just shows up in different forms: a tax bill today, a fee that compounds for a decade, years of risk you keep carrying, or years you can't touch your own money. The mistake isn't picking the wrong door. The mistake is comparing them on one dimension (usually the tax bill) when the real cost lives on all four.

The setup

Take a hypothetical: a $5 million position in a single stock, with a $1 million cost basis. That's $4 million of unrealized gain. For a California resident in the top brackets, long-term gains face roughly 37% combined: 20% federal, 3.8% net investment income tax, and up to 13.3% state (California taxes gains as ordinary income; there is no state-level capital-gains discount).

Sell it all tomorrow and the tax bill is about $1.48 million. That number is why people freeze. But holding isn't free either. A single stock can lose half its value in a year that barely registers for a diversified portfolio. The question is never "tax or no tax." It's which combination of tax, fees, risk, and lockup you'd rather own.

The four doors, side by side

The table below applies the same assumed 7% annual gross return to every path over ten years, then liquidates everything and pays the tax. Holding the return constant is deliberate: this is a comparison of tax and fee structures, not a forecast of what any investment will earn. This is an illustration, not a projection. Change the basis, the bracket, the horizon, or the return, and the numbers move; the relationships between the doors are the point.

Three things in that table deserve a closer look before the pros and cons.

First, deferral is the whole game. The two paths that defer the most tax finish ahead, not because they avoid the tax, but because the money that would have gone to the IRS keeps compounding in the meantime.

Second, fees can eat the entire benefit. The same exchange fund at 0.85% versus 1.8% is the difference between beating an outright sale and losing to it. Nothing else in the table changed.

Third, the step-up column is where deferral becomes elimination. Assets that pass through an estate currently receive a step-up in basis, which erases the deferred gain entirely. For a client whose realistic plan is to hold for life, the deferral paths aren't 5–10% better; they're 30–60% better. Estate law can change; that column depends on current rules persisting.

Door one: sell everything now

What it is. Realize the gain, pay the tax, reinvest the proceeds in a diversified portfolio.

The case for it. You de-risk on day one, and that's worth more than the table shows. The table assumes the stock earns the same 7% as the market; real single stocks don't behave that way. They carry two to three times the volatility of a diversified portfolio, and some of them go to zero. Selling also buys total flexibility: no lockup, no eligibility test, no ongoing structure to maintain. And if the owner is in a temporarily low bracket (a retirement gap year, a year with harvested losses), the tax bill can be meaningfully smaller than the headline number.

The case against it. You pay the largest possible tax bill at the earliest possible moment, and you forfeit the compounding on that money forever. If the estate step-up was realistically available, selling now converts a tax that might never have been paid into one that definitely was.

Door two: sell over time

What it is. A planned sell-down (here, 20% of the position each year for five years) with proceeds reinvested as they come.

The case for it. Deferring the later tranches lets more capital compound, which is why this path modestly beats the immediate sale despite paying more total tax. It spreads the gain across multiple tax years, which can hold some of it under bracket thresholds. And it pairs naturally with tax-loss harvesting: run the diversified sleeve as a direct-indexed portfolio during the transition, and harvested losses can offset a meaningful share of each year's sale gains. It's also psychologically executable, which matters. A plan a client actually follows beats a better plan they abandon.

The case against it. The cost isn't in the tax column; it's in the risk you keep. For five years, a large share of the client's net worth stays in one stock. One bad year for that company can exceed every tax dollar this strategy will ever save. A staged sale is a bet that the stock behaves while you exit. Sometimes it doesn't.

Door three: the exchange fund

What it is. You contribute the appreciated stock to a partnership alongside other investors with the same problem; under Section 721, nobody recognizes gain on the way in. After seven years, you can redeem a diversified basket of securities, still without triggering the gain. Your original basis carries over.

The case for it. This is the only door that defers the entire tax bill while diversifying on day one. It accepts a single concentrated stock, with no diversification test to pass. At modern pricing, the math beats an outright sale even if you liquidate at year ten, and it dominates everything if the position rides to a step-up.

The case against it. The seven-year lockup is real: redeem early and you typically get your own stock back, plus a penalty of 1–2%. Access generally requires qualified-purchaser status ($5M+ in investments), and the funds usually hold a sleeve of qualifying assets (often around 20% in real estate) to satisfy the tax rules, so you own what the partnership owns, not a clean index. The basis carryover means the tax is deferred, not gone. And the fee decides everything: at legacy pricing near 2%, the drag cancels the deferral, as the table shows. If the fund's fee is the last number you check, check it first.

Door four: the 351 exchange

What it is. Section 351 lets investors contribute appreciated securities into a newly launching ETF without recognizing gain. The shares trade from launch day with no lockup, and the basis carries over into the ETF shares.

The case for it. Day-one liquidity is the headline advantage over the exchange fund, and fees tend to run lower, roughly 0.45% to 1.5% depending on the sponsor. Inside an ETF wrapper, the deferred gain also benefits from the ETF structure's general tax efficiency going forward.

The case against it — and the part most coverage buries. A 351 exchange cannot absorb a concentrated position. The tax rules require the contributed portfolio to be diversified already: no single holding above 25% of what you contribute, and the top five holdings under 50% combined. A portfolio that is one stock fails on arithmetic. So for our hypothetical, the 351 is necessarily a hybrid: sell roughly three-quarters of the position first, pay about $1.1 million of tax on that portion, then contribute the proceeds plus the remaining appreciated shares. Most of the tax gets paid anyway, which is why the hybrid lands near the sale strategies rather than near the exchange fund. Minimums typically start around $1 million, and the funds launch on a sponsor's timetable, not yours.

Where the 351 genuinely shines is a different problem: the investor who already diversified years ago and is now sitting on an appreciated portfolio of many positions. For that person it's an elegant, liquid, low-cost deferral. It's a second-stage tool, the natural endpoint of door two, not a substitute for it.

What actually decides it

Strip away the mechanics and the decision usually turns on three questions. When will you need this money? If the answer is inside seven years, the exchange fund is out and the deferral paths lose most of their edge. Is the estate step-up realistically in play? If yes, full deferral stops being a modest optimization and becomes the dominant strategy. And how much single-stock risk can this household actually survive? A staged sale looks clever on a spreadsheet and feels different when the stock is down 40% in year two.

None of this is one-size-fits-all, and the tax mechanics here are educational, not advice. How any of it plays out depends on basis, bracket, state, estate plans, and rules that can change. Talk to your tax professional before acting on any of it.

But if you're sitting on a position like this and every option looks like a trap, that's usually a sign the options haven't been laid out side by side with your actual numbers. That's a 30-minute conversation. Schedule one here, or reach us at info@rubricadvisors.com / (415) 406-6041.

This material is for educational purposes only and does not constitute investment, tax, or legal advice. The illustrations above are hypothetical, rely on stated assumptions including a uniform 7% annual return that no investment is guaranteed to achieve, and are not projections or predictions of any actual investment result. Past performance is not indicative of future results. Rubric Advisors, LLC is a California-registered investment adviser.