An IPO lock-up period is a contractual window, typically 90 to 180 days after a company’s shares start trading publicly, during which founders, executives, directors, employees with equity, and pre-IPO investors cannot sell or hedge their shares.1Investor.gov. Initial Public Offerings: Lockup Agreements The restriction isn’t a government rule. It’s a private agreement between the company and its underwriters, written into the IPO prospectus, and enforced through contract law.
Who Is Locked Up and What the Restriction Covers
Lock-up agreements bind everyone who held equity in the company before it went public: founders, executive officers, board directors, venture capital and private equity backers, and employees who received stock options or restricted stock units.1Investor.gov. Initial Public Offerings: Lockup Agreements It applies whether the shares are fully vested, recently exercised from options, or still restricted.
The restriction isn’t limited to outright sales. Hedging strategies like short-selling or buying put options against the locked shares are blocked too. Underwriters treat any hedge as an attempt to sidestep the agreement, and the contract language explicitly covers it.
How Long It Runs and Where to Confirm the Exact Terms
Most lock-ups run 180 days from the first day of trading, though the industry range spans 90 to 180 days.1Investor.gov. Initial Public Offerings: Lockup Agreements The 180-day convention roughly covers two earnings cycles, giving public investors enough reported financials to form independent views on the stock.
To find the precise duration for a specific IPO, read the company’s S-1 registration statement on the SEC’s EDGAR database. Two sections carry the detail: “Shares Eligible for Future Sale” and the underwriting agreement portion of the prospectus. The S-1 states how many shares are subject to lock-up, the exact length, and any conditions that could change it. A typical S-1 describes insiders as having “agreed with the underwriters, subject to certain exceptions, not to dispose of or hedge any of their shares” during the restricted period “except with the prior written consent of the representatives.”2U.S. Securities and Exchange Commission. Form S-1 Registration Statement The full lock-up agreement is usually attached as an exhibit.
SEC rules require any company using a lock-up to disclose its terms in the registration documents, so the information is public before the stock even opens for trading.3U.S. Securities and Exchange Commission. Initial Public Offerings: Lockup Agreements
Why the Restriction Exists and What Breaking It Costs
Lock-ups are creatures of contract law. The SEC does not mandate them, and no federal regulation specifies a duration.3U.S. Securities and Exchange Commission. Initial Public Offerings: Lockup Agreements The lead underwriter insists on the restriction because if insiders dump shares on day one, the stock price collapses and the underwriter’s reputation suffers. The lock-up gives the market time to absorb newly issued shares and set a price based on public demand rather than insider liquidation.
Because the restriction is contractual, violations are handled as breach-of-contract claims by the underwriter. Remedies can include damages, forced disgorgement of sale proceeds, and injunctive relief. The practical fallout runs further: the underwriter community is small, and a breach damages the insider’s standing for future deals and the company’s ability to attract top-tier banks for secondary offerings.
Narrow Exceptions to the Restriction
Lock-ups are strict but not absolute. The exceptions are narrow, and most require the underwriter’s explicit consent.
Underwriter Waivers
The lead underwriter has discretion to release specific insiders early. This is rare, usually reserved for circumstances like death, divorce settlements, or severe financial hardship. When a waiver is granted, FINRA Rule 5131 requires the book-running lead manager to announce the pending release through a major news service at least two business days before the shares become tradeable.4FINRA. FINRA Rules 5131 – New Issue Allocations and Distributions The only exception to the notice requirement is a transfer for no consideration (a gift) to an immediate family member who agrees to the same lock-up terms.
Rule 10b5-1 Trading Plans
Insiders often set up pre-arranged selling plans under SEC Rule 10b5-1 during the lock-up, scheduling the actual trades for after the restriction lifts. A 10b5-1 plan is a written trading arrangement adopted while the insider holds no material nonpublic information, specifying in advance the shares, prices, and dates for future trades.5eCFR. 17 CFR 240.10b5-1 – Trading on the Basis of Material Nonpublic Information It provides a legal defense against insider trading allegations when the sales eventually execute.
One timing wrinkle matters. The SEC amended Rule 10b5-1 in 2023 to add mandatory cooling-off periods. Officers and directors must wait at least 90 days after adopting or modifying a plan before the first trade can execute, and up to 120 days in some cases. Other insiders must wait at least 30 days.6U.S. Securities and Exchange Commission. Rule 10b5-1 Insider Trading Arrangements and Related Disclosure – Fact Sheet During a 180-day lock-up, the cooling-off period usually runs concurrently with the remaining restriction. If you adopt a plan near the end of the lock-up, though, the cooling-off clock can push your first permitted trade well past the expiration date.
Transfers to Family and Trusts
Most lock-up agreements allow transfers to family members or trusts for estate planning without triggering a violation. The condition: the recipient must agree in writing to be bound by the same lock-up terms. The restriction follows the shares. Gifting stock to a spouse or moving it into a family trust doesn’t create a path to early selling.
The Automatic Extension Clause Around Earnings
Many lock-up agreements contain an automatic extension that catches insiders off guard. If the company releases earnings or announces material news during the final 17 days of the lock-up period, the restriction automatically extends by 18 days from the date of that announcement.7U.S. Securities and Exchange Commission. Lock-Up Agreement The same extension kicks in if the company announces it will release earnings within 15 to 16 days after the lock-up’s scheduled end.
The reasoning is that earnings create information asymmetry, and allowing insiders to sell immediately after material news raises insider-trading concerns even when they had no advance knowledge. The underwriter can waive the extension in writing, but it isn’t automatic. If you are counting down to a lock-up expiration date, check the earnings calendar first.
What Happens When the Lock-Up Expires
Lock-up expiration is one of the most predictable catalysts in stock trading. Academic research across hundreds of IPOs has found an average stock price decline of roughly 1% to 3% around the expiration date, paired with about a 40% jump in trading volume. The price drop tends to be permanent rather than a temporary dip that reverses.
How large the move is depends on how many shares are being released relative to the existing public float. In venture-backed IPOs, locked shares often exceed half of total outstanding stock, which creates a meaningful supply shock. Where the released shares are a small fraction of average daily trading volume, the effect may be minor. Staggered lock-up releases, strong post-IPO performance, and public hold commitments from large institutional shareholders can soften the impact.
If you are tracking an upcoming expiration, watch for Form 144 filings on EDGAR. Rule 144 requires affiliates to file notice of a proposed sale of restricted or control stock, and a cluster of Form 144 filings in the days before expiration is a reliable signal that significant insider selling is coming.
Rule 144 Volume Limits After the Lock-Up Ends
The lock-up ending doesn’t mean insiders can sell everything at once. Company affiliates (directors, officers, and anyone controlling more than 10% of voting stock) remain subject to Rule 144 volume caps. During any three-month period, an affiliate can sell no more than the greater of:
- 1% of the outstanding shares of the same class, or
- The average weekly reported trading volume during the four calendar weeks before the Form 144 filing.8eCFR. 17 CFR 230.144 – Persons Deemed Not to Be Engaged in a Distribution and Therefore Not Underwriters
For thinly traded names, the 1% cap can bite hard. A company with 100 million shares outstanding limits affiliate sales to 1 million shares per quarter, no matter how large the insider’s position. For stocks traded on OTC markets rather than national exchanges, only the 1% measurement applies.
Non-affiliates (former insiders no longer in a control relationship, or early investors who were never affiliates) face no volume limits once they have held the shares for at least six months, provided the company files reports with the SEC. The holding period is twelve months for non-reporting companies.8eCFR. 17 CFR 230.144 – Persons Deemed Not to Be Engaged in a Distribution and Therefore Not Underwriters Most pre-IPO shareholders have held their stock far longer than six months by the time the lock-up lifts, so the holding period is usually already satisfied.
Tax Timing: Why the Holding Period Matters More Than the Lock-Up Date
This is where many insiders lose money by selling too soon. Whether your gains are taxed at favorable long-term rates or at higher ordinary income rates depends on how long you held the shares before selling, measured from the date you acquired them, not from the IPO date or the lock-up expiration.
Shares held more than one year qualify for long-term capital gains rates of 0%, 15%, or 20%, depending on your taxable income and filing status. Shares held for one year or less are taxed as ordinary income, which can run as high as 37% at the top federal bracket. Founders and early employees usually clear the one-year threshold easily. Employees who exercised options shortly before or during the IPO window may not. Their shares may still be short-term when the lock-up expires.
High earners face an additional 3.8% Net Investment Income Tax on capital gains when modified adjusted gross income exceeds $200,000 for single filers or $250,000 for married couples filing jointly.9Internal Revenue Service. Net Investment Income Tax For someone selling a large block of appreciated post-IPO stock, that surtax is almost certainly in play, and combined with state income tax the effective rate on a short-term gain can approach 50% in high-tax states. Waiting a few additional months past the 180-day lock-up to clear the one-year holding period can mean tens or hundreds of thousands of dollars in tax savings on a sizable position.
When These Rules Don’t Apply
Not every path to a public listing carries an IPO-style lock-up. Companies that go public through a direct listing typically have no lock-up at all, because no new shares are being issued and no underwriter is in the room to negotiate one. Existing shareholders can sell on day one, which is part of why direct listings often see heavier initial volume.
SPAC transactions use lock-ups, but on a different schedule. Sponsor lock-ups often run a full year from the merger completion date, while the target company’s shareholders usually face the standard 180-day restriction. Hedge fund lock-ups restrict investor redemptions rather than share sales, and their terms vary widely by strategy. If your situation involves one of these structures rather than a traditional IPO, the specifics above don’t carry over cleanly.