📈IPO Lock-Up Expiration Calculator

Calculate IPO subscription, refund, and listing dates

Note: the U.S. IPO process has no retail subscription/refund step like Korea's. This tool tracks lock-up expiration instead — see the explanation below.

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How U.S. IPO Lock-Up Periods Work (and Why There's No Refund Date)

South Korea's IPO process lets retail investors subscribe directly for shares before listing, paying a deposit that's partly refunded a couple of business days later based on how many shares they were allocated. The U.S. process works differently. Underwriters allocate IPO shares mainly to institutional investors during the roadshow, and individual retail investors generally cannot subscribe or get a refund the way they can in Korea — so there's no subscription-and-refund date to track here.

What U.S. IPO investors do track closely is the lock-up period: a contractual window (typically 90 to 180 days) after the IPO during which company insiders, employees, and early investors are barred from selling their shares. Enter the listing date and the lock-up length specified in the IPO prospectus, and this calculator gives you the exact expiration date, how many days remain, and the common 90-day early-release reference date that some underwriters allow for a portion of shares.

Lock-up expirations matter because they can significantly increase the number of shares available for trading overnight, which sometimes puts downward pressure on the stock price as insiders sell. Many investors mark these dates on a calendar to watch for potential volatility. Always confirm the exact lock-up length from the company's official S-1 or prospectus filing, since it can vary by company and even by shareholder class.

Frequently Asked Questions

Why doesn't the U.S. have IPO subscription and refund dates like Korea?

In Korea, retail investors can directly subscribe to shares before listing through a broker, paying a deposit that's partly refunded based on allocation. In the U.S., IPO shares are allocated by underwriters mostly to institutional investors — there's no public subscription-and-refund system for retail investors to track.

What happens on the lock-up expiration date?

Company insiders, employees, and early investors become free to sell their shares for the first time. This often increases the number of shares available for trading and can add short-term downward pressure on the stock price.