Lockup Period

When a company goes public through an IPO, the founders, executives, early employees, and venture investors who held shares before the listing are generally barred from selling for a set period, most commonly 90 to 180 days. This restriction exists partly to reassure new public investors that insiders won't immediately flood the market with shares and drive the price down, and partly because securities regulations require it in many jurisdictions.

The lockup expiry date is watched closely by traders because it represents a potential increase in the supply of shares available to sell. Suppose a company has 10 million shares trading publicly and 40 million insider shares become eligible for sale the day the lockup expires. That sudden expansion of potential supply can create selling pressure, though insiders are not obligated to sell — and many don't, at least not all at once.

Lockup periods also appear in contexts beyond IPOs, such as private equity fund structures and certain cryptocurrency token launches, where early participants agree not to sell for a defined period after the asset becomes tradable. The end of any lockup is a scheduled, publicly known event, so it appears on market economic and earnings calendars that traders monitor for upcoming supply shifts. Understanding lockups is part of reading how market quotes work in the period around new listings.