The 10b5-1 cooling-off period is not one number. It is the later of two, capped by a third.

A director or officer's Rule 10b5-1 trading plan cannot trade until the later of two dates: 90 days after the plan is adopted, or two business days after the company files the 10-Q or 10-K covering the quarter of adoption. Whichever of those two is later governs — but never later than 120 days after adoption, which is a hard cap. Most of the mistakes we see come from tracking only the first of those three numbers.

Two clocks, not one

The rule's own text, 17 CFR 240.10b5-1(c)(1)(ii)(B), sets the cooling-off period at "the later of: (i) Ninety days after the adoption of the contract, instruction, or plan or (ii) Two business days following the disclosure of the issuer's financial results in a Form 10-Q or Form 10-K for the completed fiscal quarter in which the plan was adopted... but, in any event, this required cooling-off period is subject to a maximum of 120 days." A plan adopted early in a quarter usually clears the 90-day leg first, because the quarter's 10-Q or 10-K is still weeks away. A plan adopted near quarter end can do the opposite: the 90 days run out before the filing does, and trading stays frozen until two business days after that filing — up to the 120-day ceiling.

Three plans, three outcomes

Adopted 2 March 2026, 10-Q filed 12 May 2026. The 90-day leg lands on 31 May 2026. The filing is a Tuesday, and two business days after it is 14 May 2026. The later of 31 May and 14 May is 31 May — the 90-day leg governs, and the early filing never mattered.

Adopted 1 December 2025, 10-K filed Friday, 20 March 2026. The 90-day leg lands on 1 March 2026. Two business days after a Friday filing is the following Tuesday, 24 March 2026. The later of the two is 24 March — the disclosure leg governs, nine days past the 90-day floor, and still inside the 120-day cap of 31 March.

Adopted 1 December 2025, results not disclosed until 1 June 2026. The 90-day leg is 1 March 2026; the disclosure leg would be days later, in June. The cap at 120 days after adoption — 31 March 2026 — controls instead. Trading may begin on the cap date even though the quarter's results still had not been disclosed two business days earlier.

A person who is not a director or Section 16 officer skips both legs entirely: the period is flat 30 calendar days after adoption, no filing to wait on.

Where a reminder set at "plus 90" fails

A calendar note set at adoption plus 90 days is right in the first example and wrong in the second and third. It is wrong in the direction that matters: it tells someone trading is open on a date when it is still frozen, or it misses that a filing has pushed the date later. The fix is not a better reminder — it is tracking the actual filing date, because that is the only thing that decides which leg governs.

What this will not tell you

The cooling-off period is one condition of the rule's affirmative defense, not the whole of it — good faith has to continue throughout, and a director or officer must certify at adoption that they hold no material nonpublic information. Whether someone counts as an "officer" is a separate, function-based test under Rule 16a-1(f), and getting it wrong in the permissive direction turns a 120-day wait into a 30-day one. And any change to the amount, price, or timing of trades under a plan terminates it and starts a new one — the cooling-off period restarts from the date of the change, not the original adoption date. None of that is arithmetic, and no calculator should pretend otherwise.

We built a free calculator that runs this exact test, including the foreign-private-issuer version of the second leg (a Form 20-F or 6-K instead of a 10-Q or 10-K) and the holiday calendar for the two-business-day count: [unfoldcfo.com/free/10b5-1-cooling-off](https://www.unfoldcfo.com/free/10b5-1-cooling-off).

Sources. 17 CFR 240.10b5-1(c)(1)(ii)(B) (eCFR, fetched August 2026); business days per the federal holiday calendar in 17 CFR 240.0-3(a); Rule 16a-1(f). General information, not legal advice — your securities counsel is authoritative on whether a specific plan qualifies.