Concentrated Stock: 8 Ways to Diversify Without Blowing Up Your Tax Bill

A tech employee who has held through one good IPO and two years of appreciation often ends up with 60-80% of net worth in a single stock. The appreciation is mostly capital gain above a long-ago vest or exercise basis. Selling in size triggers 23.8% federal (20% LTCG plus 3.8% NIIT) plus state tax (up to 13.3% in California), which means a third of the position goes to taxes before diversification even starts.

The rational move is to diversify anyway. A 33% tax haircut is worse than a 10% tax haircut but better than riding a concentrated position through a 70% drawdown. That said, there are eight legitimate techniques that reduce or defer the tax cost of diversifying, each appropriate in a different situation. Most employees use none of them and either hold too long or sell inefficiently.

This guide covers the eight techniques, when each applies, the IRS rules that gate them, and the typical cost structure.

1. Straight sale with tax-loss harvesting

The baseline is to just sell, pay the tax, and diversify. The one refinement that helps almost everyone: coordinate the sale with tax-loss harvesting elsewhere in the portfolio.

Any realized capital loss in the same tax year offsets realized capital gain dollar-for-dollar. A loss in a taxable mutual fund, a single stock that went down, or an index fund you switched out of, all work. On a $1M gain with $200k of realized losses, net taxable gain is $800k, saving $47,600 of federal and state combined at high brackets.

Direct indexing (technique 4) can produce $30-80k of harvestable losses per year on a $1M portfolio, even in up markets, because the individual constituents diverge. A direct-indexed portfolio funded with cash before a large concentrated sale can generate enough losses to meaningfully offset the sale’s gain.

Pro: simple, no complex structures, capital is liquid immediately. Con: highest tax cost if no offsetting losses exist.

2. Sell in calendar-year chunks

Breaking a planned $5M sale across five tax years at $1M per year keeps more of the gain at the 15% LTCG bracket (under $501,050 single / $600,050 joint for 2025) and avoids the 3.8% NIIT surtax at lower MAGI levels.

The benefit is modest for high earners. A senior engineer making $400k of ordinary income is already in the 20% bracket plus NIIT before any capital gains, so spreading the gain does not move the capital-gain rate much. For someone with lower ordinary income (a semi-retired founder, a sabbatical), the spread can meaningfully reduce the effective rate.

The operational downside is market risk across years. A three-year staged sale locks in half the position at today’s prices and leaves half exposed to two more years of price movement. If the stock drops 40%, the remaining sale proceeds are dramatically lower.

3. Exchange funds

An exchange fund (not to be confused with ETF) is a private partnership under §721 that accepts contributions of appreciated stock from multiple investors. Each contributor receives partnership units representing a diversified basket of all the contributed stocks.

The §721 contribution is tax-free. No gain recognized at contribution. The contributor’s basis in the partnership units equals their basis in the contributed stock. Redemption rules require seven years of holding before any distribution, and the distribution is of in-kind stock (not cash) from the basket.

Typical access: accredited investor or qualified purchaser ($5M+ investable assets). Minimum contribution: $1-5M. Fees: 1-2% per year, which is high compared to passive ETFs. The seven-year lockup and the fee structure are the real cost.

Best for: holders with $3M+ of a single concentrated position who want diversification now, can wait seven years, and have the fee tolerance. Usually not appropriate for under $1M.

4. Direct indexing with loss harvesting

Direct indexing holds the individual constituents of an index (e.g., 300-500 stocks of the S&P 500) in a separately managed account instead of a fund. Losses on down stocks are realized; the portfolio tracks the index within a tight tracking error.

Against a concentrated position, direct indexing produces a steady flow of harvested losses (typically 1-3% of portfolio value per year) that offset gain realizations from the concentrated stock sale.

The math: fund a $3M direct-index sleeve alongside a $2M-per-year concentrated sale. Direct indexing generates roughly $60-90k of realized losses per year. The concentrated sale generates $2M of gain per year. Net taxable gain is $1.91-1.94M per year. Over a five-year staged sale, the saved tax is roughly $100-150k on the aggregate gain.

Provider universe: Parametric, Aperio, and several newer platforms. Fees are 0.15-0.40% of AUM, much lower than exchange funds.

5. Charitable remainder trust

A CRT accepts appreciated stock, sells it tax-free inside the trust, and pays the donor (or named beneficiary) an annuity or unitrust payment for a term of years or for life. At the end of the term, the remainder goes to charity.

Mechanics. Donor contributes $5M of appreciated stock to the CRT. The trust sells the stock, realizing no current tax. Proceeds are reinvested. The trust pays the donor a fixed percentage (typically 5-8%) of trust assets annually. The donor receives a charitable deduction at contribution equal to the present value of the charitable remainder (calculated under IRS §664 using the §7520 rate).

Income from the CRT is taxed to the donor under the four-tier system: ordinary income first, then capital gains, then tax-exempt income, then return of basis. The net effect is that gain recognition is spread out over the annuity term rather than concentrated in one year.

Best for: charitably inclined donors who want income and are willing to commit at least 10% of the contribution to eventual charitable distribution. The charitable component is non-negotiable; this is not a pure tax-deferral tool.

6. Collar or protective put

For holders who want to reduce downside risk without selling, an options collar (buy a put, sell a call) brackets the position within a defined range for a set period. The position stays on the books, no gain is realized, but the economic exposure is bounded.

Example. Stock at $100 per share, holder buys $90 puts and sells $120 calls, both expiring in 18 months. If the stock drops below $90, the puts pay the difference. If it rises above $120, the calls are exercised and the shares are called away at $120. Between $90 and $120, no option exercise.

Tax treatment: puts generally do not trigger constructive sale under §1259 as long as the strike is far enough below current price. Calls written at or above current price are fine. Calls written deeply in the money can trigger constructive sale (IRC §1259(b)) and treat the position as sold immediately for tax purposes.

Best for: holders who need to hold for tax or reputational reasons (founder lockup, 10b5-1 constraints, upcoming liquidity event) but want to limit downside. Typically used for 6-24 months, not indefinitely.

7. Qualified Opportunity Zone fund

Gains rolled into a Qualified Opportunity Fund within 180 days of sale defer recognition until December 31, 2026 (or fund sale, whichever is earlier). If the QOF investment is held for 10 years, any appreciation in the QOF itself is tax-free.

The deferral is real but limited. The deferred gain still comes due in 2026 (for current rules; legislation has been proposed to extend). The 10-year tax-free-appreciation benefit applies only to the QOF’s own returns, not the deferred portion.

QOFs invest in designated opportunity zones, which are primarily real estate and small-business projects in census tracts meeting specific criteria. Return profile is typically 8-12% IRR target with meaningful illiquidity. Not a passive index substitute.

Best for: holders with meaningful gains who want deferral and are comfortable with real-estate-heavy illiquid investments. The shrinking window until 2026 recognition makes new QOF investments less attractive than they were in 2018-2021.

8. Gifting to family or charity

Appreciated stock gifted to charity qualifies for a fair-market-value charitable deduction (up to 30% of AGI limit for long-term holdings) with no capital gain recognition. A $100,000 gift of stock with $10,000 basis saves roughly $18,000 of capital gains tax that would have been owed on a sale-and-donate sequence, and yields a $100,000 deduction at the donor’s marginal rate.

Donor-advised funds accept appreciated stock, sell it tax-free, and the donor recommends grants to charities over time. Similar mechanics for private foundations, though with stricter operational requirements.

For family gifts, annual exclusion is $19,000 per donor per recipient in 2025, lifetime exclusion $13.99M per donor. Gifting appreciated stock to adult children in lower tax brackets transfers future appreciation and the embedded gain. The recipient sells later at their own bracket.

Best for: holders with clear charitable intent, or who plan to gift significant wealth to family anyway and want to accelerate the transfer at today’s valuations before further appreciation.

Choosing an approach

For a $500k concentrated position, techniques 1, 2, and 4 (sell, stage over years, pair with direct indexing) usually suffice. The more complex structures (exchange fund, CRT, QOF) have fixed costs that overwhelm the tax benefit at smaller sizes.

For a $2-10M position, exchange funds and CRTs start to make sense depending on the holder’s charitable intent and lockup tolerance. Direct indexing as a loss-harvesting companion is almost always valuable.

For a $10M+ position, the full toolkit is typically deployed in combination: staged sale, direct indexing, partial CRT for charitable portion, and possibly exchange fund for a chunk. The cost of execution (attorney, CPA, advisor fees) is negligible relative to the tax savings.

Frequently asked

How concentrated is too concentrated? A common rule is no more than 10-15% of net worth in any single position. For tech employees, holding 20-30% of their employer is tolerable if the person acknowledges the concentration and plans an explicit exit. Above 30%, the risk-adjusted return is almost always improved by diversification even after tax.

Can I just use stop-loss orders? Stop-losses on concentrated positions often execute at the worst price in a crash (gaps down through the stop). They provide some protection but are not a substitute for reducing the position. A protective put is more reliable but more expensive.

What about borrowing against the stock instead? A securities-based line of credit or pledged asset line provides liquidity without selling. Rates are tied to SOFR plus a spread (currently 6-9% all-in). Useful for short-term liquidity (a down payment) but expensive as a long-term diversification substitute. Also creates margin-call risk if the stock drops.

Do I need all these structures, or just one? Most people need one or two. The right answer depends on portfolio size, charitable intent, and how quickly you want out of the position.

What about a prepaid variable forward? A PVF is an advanced structure similar to a collar but structured as a single contract delivering shares at a future date for cash now. Tax treatment under §1259 is complex. These exist but are typically deployed by institutional holders, not individuals.

Next step

Start with a candid assessment of your concentration percentage and the basis/gain breakdown. The concentrated-stock calculator models the after-tax proceeds under each technique. For positions above $2M, talk to a CFP who specializes in concentrated stock before executing any single technique; the interactions between techniques (direct indexing alongside a staged sale is better than either alone) are where the real optimization lives.