Insights

How to Track Lock-Up Expirations From S-1 Filings

Alphanume Team · May 11, 2026

Reading lock-up language in S-1 prospectuses to date the supply event correctly.

The S-1 registration statement is the source document for traditional-IPO lock-ups. It contains the lock-up agreement signed by directors, officers, and significant pre-IPO holders — and it specifies the duration, the anchor date, and any exception clauses. Reading this language correctly is the foundation for any IPO lock-up calendar.

Where the lock-up appears in the S-1

An S-1 prospectus discloses the lock-up in two main places:

The "Shares Eligible for Future Sale" section in the body of the prospectus. This narrative section summarizes the lock-up restrictions and identifies which shareholders are bound.
The lock-up agreement itself, filed as an exhibit to the registration statement (typically Exhibit 1.1, 1.2, or 10.X depending on the company's exhibit numbering).

The narrative section is useful for a summary; the exhibit contains the binding terms.

The standard 180-day lock-up

The default IPO lock-up runs 180 days from the date of the prospectus. The standard formulation:

"For a period of 180 days from the date of this prospectus, the directors, executive officers, and certain other holders of our common stock have agreed not to, without the prior written consent of [Underwriters], offer, sell, contract to sell, pledge, or otherwise dispose of any shares of common stock or any securities convertible into or exercisable for common stock."

Key components to extract:

Duration: 180 days.
Anchor: Date of the prospectus (typically the day of pricing).
Restricted parties: Directors, executive officers, plus identified pre-IPO holders.
Permitted transferees: Often estate-planning vehicles, charitable transfers, exchange transactions.
Waiver provision: Underwriters can waive at their discretion.

Non-standard variants

Many IPOs deviate from the 180-day default:

Early-release at threshold price. Some lock-ups release at 90 days if the stock trades above a defined threshold for a defined number of trading days. The trigger language follows the de-SPAC convention closely.
Staggered releases. Some lock-ups release a defined percentage of shares at intermediate dates. E.g., 25% at 90 days, 50% at 180 days, 100% at 365 days.
Different durations for different holder groups. Founders may have longer lock-ups than rank-and-file employees.
Earnings-window releases. Some lock-ups release at the second 10-Q post-IPO if the company beats certain financial thresholds.
Direct-listing structures. Direct listings typically have no underwriter lock-up at all. Insiders are free to sell immediately.

The non-standard variants are common enough that no extraction pipeline should hard-code 180 days.

Extracting from the document

Approaches in order of complexity:

Regex on common phrasings. Most S-1 lock-up language follows recognizable templates. A handful of patterns covers the majority of the universe.
Section identification + LLM extraction. Locate the "Shares Eligible for Future Sale" or "Underwriting" section, then use an LLM to extract structured fields. More flexible.
Full-document LLM extraction with verification. Run extraction against the full prospectus with explicit field schema, then verify against the exhibit. Most thorough.

For non-standard structures (staggered releases, early-release triggers, earnings-window releases), the LLM approaches handle the variability better than regex.

Common parsing pitfalls

Confusion of "prospectus date" with "IPO pricing date." Usually the same day, but not always. The prospectus date is the canonical anchor.
Overlooking earlier-release triggers. A lock-up "ending 180 days after the prospectus date, or earlier if X" must capture both branches.
Counting calendar days vs trading days. Lock-ups are almost always specified in calendar days. Convert to dates carefully.
Missing amended lock-ups. Lock-ups can be amended by mutual consent and the amendment is disclosed in subsequent 8-Ks. The amended terms supersede.
Multiple lock-up agreements. Different holder groups may have different lock-up agreements. Reading only one and extrapolating is a common error.

Cross-checking

To validate extracted lock-up terms:

Compare extracted expiration date against any third-party trackers.
Check insider Form 4 filings around the predicted expiration date — sales should cluster within days of expiration if the lock-up is correctly identified.
Read the first 10-Q post-IPO; companies sometimes restate the lock-up terms.

For non-IPO lock-ups

The same extraction approach applies to other lock-up contexts:

De-SPAC lock-ups in DEFM14A and merger 8-K exhibits — see SPAC lock-up expiration.
PIPE lock-ups in subscription agreements filed as 8-K exhibits.
Secondary-offering lock-ups in 424B5 prospectus supplements.

Where Alphanume fits

Alphanume's Dilution Events dataset parses lock-up terms from S-1, merger, and PIPE filings, producing a unified calendar of upcoming lock-up expirations across the universe. The parsing handles staggered releases, early-release triggers, and lock-up amendments.

Explore the Dilution Events dataset →