IPO Lock-Up Expiry
The date when insiders and early investors of a newly public company are first contractually allowed to sell their shares.
What it is
When a company goes public, its founders, employees, and pre-IPO investors normally sign an agreement with the underwriters promising not to sell their shares for a set stretch of time after the offering. That stretch is the lock-up period, and the day it ends is the lock-up expiry. The length is written into the final prospectus (SEC Form 424B4) — 180 days is the most common term, but 90, 120, and staggered or tiered arrangements all appear, so the actual wording matters more than any rule of thumb. Once the lock-up lapses, those previously restricted shares become eligible to trade, which increases the free float — the portion of shares actually available in the market. The restriction is contractual rather than statutory, so underwriters can and sometimes do release holders early.
Why it matters
Lock-up expiry is one of the few post-IPO dates a researcher can know well in advance, because it is disclosed in writing on day one. It matters mainly because the tradable float can change substantially — a company that floated 15% of its shares may see much of the remaining 85% released from the contractual restriction on a single date, though affiliates remain subject to Rule 144 conditions on how they sell — which is context worth knowing when reading price and volume behaviour around that period. It also shapes how you interpret insider transaction filings: a Form 4 sale by a locked-up insider would breach the underwriting agreement rather than any statute, so such sales are uncommon before expiry unless the underwriters grant a waiver or the transfer falls under a carve-out. A pitfall is treating expiry as a prediction: eligibility to sell is not the same as selling, insiders frequently hold, underwriters may waive the lock-up early or release holders in tranches, and academic evidence on price effects around expiry is mixed and heavily dependent on the specific company. The date is a research signal that tells you when a known supply constraint lifts — it is not a verdict on what will happen.
How it's calculated
There is no model or coefficient here — the entry is a parsed fact, so accuracy depends entirely on reading the filing correctly. The inputs are the final prospectus (SEC Form 424B4), specifically the "Shares Eligible for Future Sale" and "Underwriting" sections, which state the lock-up length in days and the date it runs from. The arithmetic is simply the stated start date plus the stated number of days, giving the calendar date on which the restriction lapses. Because underwriters can waive a lock-up early and many agreements contain conditional early-release clauses, the computed date is the contractual default rather than a guaranteed date. For that reason the source sentence should be read verbatim rather than reduced to a single date.
How Quintarthai uses it
Quintarthai's IPO screener parses the lock-up period directly from the 424B4 prospectus and shows the verbatim quoted sentence, so you can read the underlying wording rather than trust a computed figure. This is educational disclosure surfacing only — the platform shows what the filing says and never tells you what to do about it. See /app/.