HNW Tax Strategy Guide

Section 351 Conversion ETFs

Diversifying multi-million-dollar single-stock positions into publicly traded ETFs with immediate liquidity and tax-deferral of built-in gains.

← Back to All Tools
Liquidity Advantage

While legacy §721 exchange funds impose a restrictive 7-year illiquidity lock-up and hold illiquid real estate, modern §351 conversion ETFs provide immediate public market liquidity upon contribution while deferring capital gains under corporate nonrecognition rules.

Modern Nonrecognition Strategy

Section 351 Conversion ETFs vs. Legacy 721 Exchange Funds

§351

351 Conversion ETFs (Immediate Public Liquidity)

  • Immediate Public Market Liquidity: Investors receive exchange-traded ETF shares immediately—no 7-year lock-up—allowing trading on public stock exchanges at any time.
  • IRC § 351 Corporate Nonrecognition: Concentrated stock is contributed into a newly formed ETF under corporate nonrecognition rules without triggering immediate capital gains tax.
  • § 368(c) Control Test: Requires contributing investors collectively hold 80%+ control immediately after exchange. The ETF diversifies holdings via tax-free in-kind swaps.
  • Bespoke ETF Issuers: White-labeled and managed by specialized ETF platform sponsors and asset managers.
§721

Legacy §721 Exchange Funds

  • Mandatory 7-Year Lock-Up: Investors are locked into limited partnership units for 7 years before redeeming into public stocks.
  • 20% Illiquid Requirement: Must hold at least 20% of assets in illiquid real estate to satisfy § 721(b) investment company rules.
  • Private Partnership Structure: Sponsored primarily by traditional Wall Street private wealth divisions.
Statutory Diversification Analyzer

IRC § 351(e) 25/50 Rule Composition Calculator

Evaluate whether your contributed portfolio satisfies the statutory 25% single-stock and 50% top-five holdings caps, including look-through aggregation from ETF & mutual fund holdings.

Portfolio Component Inputs

Direct shares of your main target stock position.

Combined direct value of your 2nd, 3rd, 4th, and 5th largest individual stock holdings.

Value of ETFs or mutual funds contributed to the portfolio (e.g. S&P 500, QQQ, XLK).

%

Under IRS § 351(e) look-through rules, ETF holdings of this stock are aggregated into your total position weight.

• Note: Any unallocated balance (Total Contributed Portfolio minus Itemized Holdings) is treated as non-concentrated, already-diversified assets under § 351(e) math.

Statutory Method Note (Treas. Reg. § 1.351-1(c)(6)):

Under IRS rules, nonrecognition treatment under § 351 requires that each contributing transferor transfers an already statutorily diversified portfolio (or that the transfer does not result in diversification). Look-through rules apply to broad funds and ETFs to prevent circumvention of the 25% single-issuer and 50% top-five limits.

Interactive Assessment

Concentrated Stock Eligibility Quiz

Answer 3 questions to evaluate structural suitability and liquidity alignment.

Independent Fiduciary Network

Need Guidance on a Section 351 Conversion ETF Strategy?

Section 351 ETF contributions require specialized platform sponsors, 80% control group coordination, and § 351(e) statutory diversification checks. Click to be connected with an independent, fee-only CFP® specializing in concentrated stock strategies and 351 ETF conversions.

Risks & Considerations

Key Disclosures & Fee Structures

Tax Deferral, Not Elimination:

Both §721 exchange funds and §351 conversion ETFs operate under carryover basis rules. Your original cost basis transfers into the new shares, preserving built-in capital gains. Permanent tax elimination occurs only if shares are held until death (receiving a step-up in basis under IRC § 1014) or donated to qualified charities.

Fee Layering Warning:

Always evaluate all-in fee structures. Exchange funds often combine management fees with eventual redemption or conversion charges. 351 ETFs impose fund-level management fees. Ensure prospective advisors disclose total net fees across all layers.

Advanced Tax Analysis

Technical Deep Dive: IRC § 351 Nonrecognition Mechanics & The Diversification Exception

A statutory analysis of corporate formation rules, control requirements, and Section 351(e) investment company traps.

1. Statutory Framework: IRC § 351(a) General Nonrecognition

Under Internal Revenue Code Section 351(a), no gain or loss is recognized if property (including appreciated corporate stock) is transferred to a corporation by one or more persons solely in exchange for stock in such corporation, provided that immediately after the exchange such person or persons are in "control" of the corporation.

The 80% Control Requirement (IRC § 368(c)):

For purposes of § 351, "control" is defined under IRC § 368(c) as the ownership of stock possessing at least 80 percent of the total combined voting power of all classes of stock entitled to vote and at least 80 percent of the total number of shares of all other classes of stock of the corporation. In a § 351 conversion ETF, contributing investors act as a single transferor group to satisfy the 80% control threshold at initial fund formation.

2. The Investment Company Anti-Abuse Trap: IRC § 351(e)(1)

Ordinarily, transferring single-stock positions into a new corporate entity to trade for other stocks would trigger immediate gain recognition. To prevent tax-free "swap funds," Congress enacted IRC § 351(e)(1), which denies § 351 nonrecognition treatment to transfers made to an "investment company."

Under Treas. Reg. § 1.351-1(c)(1), a transfer is treated as a transfer to an investment company if two conditions are met simultaneously:

  1. The transfer results, directly or indirectly, in diversification of the transferors' interests; AND
  2. The transferee is a Regulated Investment Company (RIC), Real Estate Investment Trust (REIT), or a corporation where more than 80 percent of its total asset value consists of held-for-investment stock, securities, cash, or REIT shares (under the expanded asset definition enacted in the Taxpayer Relief Act of 1997).

3. Per-Transferor Diversification Rules (Treas. Reg. § 1.351-1(c)(6))

Because a newly formed ETF is an investment company holding >80% securities, § 351 nonrecognition hinges entirely on whether the contribution results in diversification. Crucially, Treasury Regulations apply the diversification safe harbor on a per-transferor basis:

The 25% / 50% Statutory Diversification Test (IRC § 368(a)(2)(F)(ii)):

Under Treas. Reg. § 1.351-1(c)(6)(i), a contribution of stock is NOT treated as resulting in diversification if each individual transferor transfers an already statutorily diversified portfolio where:

  • No single stock or issuer represents more than 25 percent of total contributed asset value; AND
  • The aggregate value of the top five holdings does not exceed 50 percent of total contributed asset value.
Per-Transferor Statutory Restriction:

An investor cannot contribute a 100% single concentrated stock position by itself under Section 351. The transferor group as an aggregate cannot shield an un-diversified single stock holder. To participate tax-free, the investor must pair their concentrated stock with cash, other equities, or existing diversified funds within their own contributed basket prior to exchange (utilizing IRS look-through rules under Treas. Reg. § 1.351-1(c)(6)(ii) for ETF holdings).

4. How the ETF Diversifies Post-Contribution: TRS Overlays & In-Kind AP Baskets

Once pre-diversified baskets enter the ETF under Section 351, the fund holds physical low-basis stocks that may not match its target benchmark index. ETF sponsors navigate portfolio convergence tax-free using two primary financial mechanisms:

A. Total Return Swaps (TRS) Synthetic Overlay:

Total Return Swaps do not alter physical cost basis or eliminate taxes directly. Instead, the ETF uses Total Return Swaps as an interim synthetic overlay. Immediately post-conversion, the ETF swaps out the economic returns of over-weighted contributed shares for the total return of the target index (e.g. S&P 500), tracking index NAV performance while physical shares await redemption.

B. Custom In-Kind AP Redemptions (IRC § 852(b)(6) & SEC Rule 6c-11):

To eliminate low-basis physical single stock without paying corporate tax, the ETF utilizes Subchapter M redemption rules under IRC § 852(b)(6) and SEC Rule 6c-11. When institutional Authorized Participants (APs) redeem ETF creation units, the fund delivers out appreciated low-basis single stock in-kind via custom redemption baskets. Under § 852(b)(6), the ETF recognizes zero realized capital gain, permanently purging low basis from the fund wrapper.

5. Substituted Basis, Inside Basis & Tacking Rules

Tax Dimension Governing IRC Code Statutory Mechanics
Investor Outside Basis IRC § 358(a)(1) Investor receives a substituted basis in ETF shares equal to their aggregate historical cost basis in contributed assets.
ETF Inside Basis IRC § 362(a)(1) ETF takes a carryover basis in contributed securities equal to the transferor's adjusted historical basis.
Holding Period Tacking IRC § 1223(1) & (2) Investor tacks stock holding period onto ETF shares; ETF tacks investor holding period onto contributed securities.
Executive Compensation Planning

Relocating States With Concentrated Stock or RSUs?

Sourcing concentrated equity or RSU gains across state lines requires audit-proof domicile documentation to prevent dual-state taxation.

Read RSU State Sourcing Rules →

Explore Related High-Net-Worth Tax Tools