THE BARATELLI INSTITUTE · Mentoring at Scale
FOR FOUNDERS, EXECUTIVES, AND POST-LIQUIDITY-EVENT WEALTH HOLDERS

The single-stock concentration risk that destroys more wealth than any other mistake.

One stock at 30%+ of net worth is a structurally underdiversified portfolio — even if that stock has been the source of all the wealth. Here are the six tax-aware unwinding strategies modeled side-by-side: 10b5-1 disciplined selling, §721 exchange fund, charitable remainder trust, zero-cost collar, direct-indexing tax-loss harvesting, outright sale. After-tax NPV, time-to-diversified, and the trade-offs each one buys you.

30%+
"Concentrated" threshold
6
Strategies modeled
7-yr
Exchange-fund lockup
23.8%
Federal LTCG + NIIT
YOUR POSITION
1
The position
2
Tax position
3
Goals & constraints
4
Strategy preferences
5
Strategy comparison
STAGE 1 OF 5

The concentrated position

Defaults model a $5M concentrated stock position with a $500K cost basis (90% embedded gain) — typical post-IPO founder or long-tenured tech executive.

Drives strategy availability. Public stock has the full menu (collar, 10b5-1, exchange fund). Private stock has fewer paths (sale to PE secondary, structured liquidity, exchange-fund variants if liquid event has occurred).
Determines available legal mechanics. Founder/early-employee shares may qualify for QSBS §1202 exclusion. ISO-exercised stock has special holding-period rules for LTCG. RSU vesting created cost basis at vest.
Today's market value of the concentrated holding.
$
Total tax basis. For founder shares: usually near-zero. For RSU stock: FMV at vest (the W-2 income amount). For ISO stock: exercise price + AMT adjustment if applicable. For inherited: stepped-up basis at decedent's death.
$
All marketable assets — this stock plus brokerage, cash, retirement accounts, other public investments. Excludes primary residence, illiquid alternatives, business interests other than this stock.
$
If founder shares meet the §1202 tests (5-year hold, original-issue C-corp, qualifying business, asset test), gain on sale up to the per-issuer cap ($15M post-OBBBA) is FEDERAL TAX FREE. Materially changes the analysis. See the QSBS Calculator for full eligibility check.
Why this is the most-mismanaged decision in private wealth. Founders and executives anchor on the stock that made them wealthy. Selling feels like betraying the source of success. But concentration risk is real: a single stock can lose 30-70% in any given 12-month window — Enron, GE, Lehman, Meta in 2022, every single tech stock in 2000-2002. The discipline isn't to sell now; it's to have a written plan that diversifies systematically over a defined window with the lowest after-tax cost. That's what this tool models.
STAGE 2 OF 5

Tax position

Federal LTCG + NIIT + state determines the cost of an outright sale. The other strategies trade off some of that tax cost against time, liquidity, or complexity.

20% for AGI above $533K single / $600K MFJ in 2025; 15% below. Most concentrated-position holders are at the 20% top rate.
State tax on capital gain varies enormously: FL/TX/TN/NV/WA = 0%; CA = 13.3%; NY = 10.9%. Establishing residency in a no-tax state BEFORE selling is the highest-leverage tax move available — see the State Tax Migration tool.
3.8% surtax on net investment income for AGI above $200K single / $250K MFJ. Almost certainly applies to anyone with a meaningful concentrated position.
Drives whether CRT (Charitable Remainder Trust) and CLAT (Charitable Lead Annuity Trust) strategies are viable. CRT requires a charitable remainder beneficiary; CLAT works for the highly charitable who also want to pass wealth to heirs.
STAGE 3 OF 5

Goals & constraints

Time horizon, liquidity needs, and any restrictions on selling all narrow the strategy menu.

How quickly do you want concentration eliminated? Shorter = pay more tax now or use derivatives. Longer = stretch sales, exchange funds (7-year lockup), or charitable trusts.
Cash needed for known expenses (real estate purchase, business investment, tax bill, lifestyle). Strategies with multi-year lockups (exchange fund, CRT) don't help if you need liquidity now.
$
Insider trading rules (10b5-1 required for affiliates), lockup expirations, blackout windows around earnings, post-IPO 6-month lockup. For affiliates (officers, directors, 10%+ owners), Rule 144 limits volume to greater of 1% of shares outstanding or 4-week trading volume per quarter.
If you genuinely believe the stock will outperform, slower diversification has option value. If you think it's fully valued or vulnerable to drawdown, speed matters more. Be honest — most concentrated holders are systematically over-optimistic about the stock that made them wealthy.
The single-stock-vs-S&P empirical record. Hendrik Bessembinder's research (2018, 2023) found that just 4% of all listed U.S. stocks account for the entire net dollar-weighted gain of the U.S. equity market over the entire long-term history; the remaining 96% returned at or below T-bills. Even excluding total losses, the median single stock substantially underperforms the index. Any concentrated holder believing "this one is different" needs to confront the empirical fact that 4% of stocks win — and the rest don't, even after producing meaningful intermediate returns.
STAGE 4 OF 5

Strategy preferences

Each strategy has a different complexity, cost, and result. Set your preferences here; the next stage compares all six side-by-side at your inputs.

Outright sale = simplest. 10b5-1 = simple but requires plan filing. Direct indexing = ongoing management. Collar / exchange fund = moderate complexity. CRT / CLAT = legal documents, irrevocable trust, ongoing administration.
Strategies have different ongoing costs. Sale = 0%. 10b5-1 = ~10 bps. Direct indexing = 25-50 bps + legal setup. Exchange fund = 75-150 bps + 7-year lockup. CRT = 50-100 bps + setup ($15-50K) + ongoing trustee/admin.
Used to compute NPV across strategies with different time horizons. For wealthy private investors, 5-7% is typical (mix of equity-like opportunity cost and patient capital nature). Higher discount rate favors faster-resolution strategies; lower favors patient strategies (CRT, exchange fund).
%
Long-term expected return on a diversified equity portfolio post-diversification. Historical S&P 500: ~10% nominal, ~7% real. Use 6-7% if conservative, 8-9% if more bullish on equity returns.
%
STAGE 5 OF 5 · STRATEGY COMPARISON

Side-by-side strategy comparison

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Concentration: today vs. post-strategy

All six strategies — after-tax NPV

Outright-sale waterfall (the baseline cost)

Decision metrics

Recommendations

PAIRS WITH
FO Reference Guide · Liquidity Event Playbook · QSBS Calculator · State Tax Migration
The Liquidity Event Playbook covers the broader set of post-liquidity decisions: residency planning, charitable structuring, real estate placement, and the multi-year sequencing of large taxable events. If your shares may qualify for QSBS §1202 exclusion, run the QSBS Calculator first — that single test changes the entire after-tax economics. Subscribe to the library →
FO REFERENCE GUIDE

Diversification is one decision. The full post-liquidity playbook covers the others.

State residency planning · charitable structuring (DAF / CRT / CLAT) · trust selection (revocable, irrevocable, dynasty) · investment policy statement · estate-tax exemption planning · concentrated-stock unwinding · real estate placement · the multi-year sequencing of tax events.

Each strategy is a complex legal/tax structure with material variation by facts. The model uses standard market conventions but does not separately model: 10b5-1 plan-design rules (current SEC mandatory cooling-off period of 90-120 days), §721 exchange-fund subscription mechanics (qualifying-investment requirements, "soft" vs "hard" sub periods), §664 CRT actuarial requirements (10% remainder minimum, §7520 rate sensitivity), CLAT income-tax-charitable-deduction mechanics, collar margin requirements, or direct-indexing portfolio-management ASC 740 implications. Engage tax counsel, a CFP, and a sophisticated wealth manager for any actual implementation. The empirical research on single-stock-vs-index returns cited (Bessembinder 2018, 2023) is academic; individual stock outcomes vary. This is not investment, tax, or legal advice.
WANT THE METHODOLOGY BEHIND THIS TOOL?
This calculator is one chapter of The Liquidity Event Playbook.
The tool gives you the answer. The guide gives you the argument — the case law, the worked examples, the negotiation playbook, the cross-check tables, the exception cases. Read the chapter and you can defend your number to a board, a buyer, an examiner, or a counterparty.
The methodology behind this calculator is in Ch 9 Rollover Equity of the reference guide.
See the Guide → Browse all 22 guides
PROFESSIONAL DISCLAIMER · PLEASE READ

Educational and informational purposes only. This calculator and any output it produces are intended solely for general educational and decision-support purposes. They do not constitute investment, tax, legal, accounting, appraisal, lending, insurance, or any other professional advice, and they do not create a fiduciary, attorney-client, accountant-client, or advisor-client relationship of any kind.

Estimates based on your inputs. All results are estimates derived from the data and assumptions you provide. Tax law, accounting standards, regulations, market conditions, and the specific facts of your situation can materially change the answer. The Baratelli Institute, its affiliates, and any co-branding professional make no warranty of accuracy, completeness, currency, or fitness for any particular purpose, and disclaim all liability for decisions made in reliance on the output.

Consult your own qualified professionals. Before acting on anything calculated here, consult your own attorney, CPA, financial advisor, appraiser, lender, or other qualified professional licensed in your jurisdiction who has reviewed your specific facts and applicable current law. The Baratelli Institute is a publisher of practitioner reference material. It is not a registered investment adviser, broker-dealer, law firm, accounting firm, appraisal firm, or lender.

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