Lock-up period

A lock-up period is a contractual prohibition on selling shares held by company insiders, employees, and early investors, typically lasting six months after an initial public offering. Lock-up agreements are standard in IPOs to prevent mass insider selling immediately after the stock goes public, which would depress the price and signal insider pessimism. Upon expiration, insiders are free to sell, which often causes a temporary stock price dip.

Why lock-up periods exist

An IPO dramatically increases a company’s share price (many IPOs gain 10–50%+ on the first day). Without a lock-up, insiders would be tempted to sell immediately to cash out their pre-IPO stakes at the new, inflated price.

If all insiders sold at once:

• Massive supply of shares floods the market.
• Stock price crashes.
• New public shareholders suffer immediate losses.
• The IPO is viewed as unsuccessful; underwriters struggle to attract future IPO clients.

Lock-ups align insider and public interests: both groups benefit from price stability in the post-IPO period. Insiders who want liquidity can accept a lower IPO price in exchange for a higher expected price post-lock-up. Public shareholders get price stability.

Standard lock-up terms

Typical 6-month lock-up:

• IPO closes on January 1.
• Lock-up expires on July 1 (6 months later).
• Insiders can sell on and after July 1.

Extended lock-ups are sometimes negotiated:

• Tech company IPOs often have 6–12 month lock-ups.
• Some agreements include “tiered” releases (e.g., 50% unlock after 6 months, remaining 50% after 12 months).

The lock-up period is specified in the underwriting agreement and is binding on all parties.

Who is locked up

• Founders and company officers.
• Board members and directors.
• Early employees with option grants.
• Venture capital and private equity investors.
• Strategic investors who bought pre-IPO shares.

Not everyone: public shareholders who buy stock in the IPO or secondary market are not locked up.

Exceptions and waivers

Lock-up agreements typically include limited exceptions:

• Gifts: Founders can gift shares to family (though the recipient is usually also locked up).
• Estate settlement: If a locked-up founder dies, their estate may be allowed to sell.
• Cashless exercises: Employees exercising options via cashless exercise and immediately selling can sometimes do so (debated).
• Leverage-driven sales: Sales to cover taxes or margin calls may be allowed.
• Company repurchase: If the company buys back shares, it does not count as insider selling.

Underwriters strictly enforce lock-ups; violations can trigger lawsuits and damages.

Lock-up expiration and stock price

Lock-up expiration is a key event:

Market expectations: As the lock-up expiration date approaches, the market anticipates insider selling. This is often reflected in a gradual stock price decline in the weeks leading up to expiration.

At expiration: Insiders who want liquidity sell. This can cause a significant 1-day or multi-day stock price drop (5–10% or more for stocks where insiders hold large stakes).

Post-expiration: If insiders don’t sell (signaling confidence), the stock may rally.

Strategic and accidental sales

Some insiders deliberately delay sales or sell in tranches to avoid market impact. Others cash out immediately. The market interprets heavy insider selling as negative signal (insiders lack confidence in future prospects).

Conversely, if lock-up expires and insiders do not sell, it signals confidence, which can boost the stock.

Waiver and extension negotiations

Sometimes, underwriters and insiders negotiate to waive or extend lock-ups:

Waiver: Underwriter agrees to release the lock-up early (e.g., 90 days instead of 180). This might happen if the stock has performed exceptionally well and the market is strong.

Extension: Underwriter and insiders mutually agree to extend lock-up (e.g., 6 months to 12 months) if conditions are poor or the company wants to signal confidence.

Waivers and extensions require consent from all parties; they are not automatic.

Lock-up in secondary offerings

Secondary offerings often trigger lock-up releases:

• Founder conducts secondary offering; sells 10 million shares to the public at IPO price + 5%.
• Secondary offering proceeds are released from lock-up contract; founder can sell directly to the public.
• Remaining 40% of founder’s shares remain locked up until standard lock-up expiration.

Calculating lock-up impact

A company has:

• 100 million shares outstanding post-IPO.
• Founders hold 30 million locked-up shares.
• Public float (freely tradeable) is 70 million shares.

Upon lock-up expiration, an additional 30 million shares become tradeable:

• Public float increase: 30 million shares × stock price.
• Potential selling pressure: If founders sell half their shares, 15 million shares hit the market.

For a stock trading at $50, this represents $750 million in potential selling pressure.

Correlation with stock price patterns

Studies show:

• Stock often declines slightly in the weeks before lock-up expiration (anticipation of selling).
• Stock often declines more sharply in the week of expiration (actual selling).
• Stock often stabilizes after a week or two if no disaster occurs.

Some investors avoid buying stocks shortly before lock-up expiration, expecting downward pressure.

Founder liquidity and wealth

For founders, the lock-up period is a hardship: they cannot sell even if they want or need to (e.g., to diversify, pay taxes, or pursue other investments). Lock-up is negotiated; some founders request shorter locks or tranched releases.

At lock-up expiration, founders often finally achieve meaningful liquidity and can diversify their wealth. This is an important psychological milestone.

Post-IPO regulation vs. contract

Lock-ups are contractual agreements (in the underwriting agreement), not SEC regulations. The SEC does not mandate lock-ups. However, underwriters as a market practice require lock-ups for all IPOs.

In rare cases (small IPOs, specific industries), lock-ups are shorter or waived, but this is unusual.