What Rule 10b5-1 Plans Do to an Insider Buying Signal

Two insiders each file a Form 4 showing a code-P purchase of 20,000 shares on the same day. One decided to buy that morning after watching the stock fall. The other bought because a schedule they set up eight months ago told a broker to.

Those are very different pieces of information, and on the face of the filing they look nearly identical. Telling them apart is one of the highest-value skills in reading insider data — and one of the most commonly skipped.

What Rule 10b5-1 actually does

Corporate insiders have a permanent problem: they almost always know something the market doesn't. That makes trading their own stock legally hazardous, because trading while in possession of material non-public information is insider trading.

Rule 10b5-1, adopted by the SEC in 2000, gives them a way out. If an insider sets up a written plan specifying the amount, price and timing of future trades — or hands that discretion to someone else — at a time when they do not possess material non-public information, trades executed later under that plan get an affirmative defence. The reasoning is straightforward: you cannot be trading on inside information if you committed to the trade before you had any.

In practice this is how most executives transact at all. Without it, an insider at a company with a continuous news flow might never have a clean window.

Why a planned buy carries less signal

The entire case for insider buying rests on one idea: the purchase is a decision, made at a specific moment, with information about how the business is going. That is why buying is cleaner than selling and why several insiders deciding at once means more than one.

A 10b5-1 plan deliberately severs the link between the decision and the moment.

• The information is stale. A plan adopted in January and executing in September reflects what the insider believed in January.
• The timing is not a choice. The purchase happens on the plan's schedule, not because the stock got cheap. A plan buy on a day the stock dropped 20% is a coincidence, not a vote of confidence.
• Clusters can be manufactured by accident. If several executives adopt similar plans after the same compensation cycle, their purchases can land in the same window and look like coordinated conviction when they are really a shared calendar.

That last point matters most for anything built on cluster detection, including this site. It is the main reason our methodology lists routine and plan-based purchases as a known limitation rather than pretending the filter is perfect.

What the 2022 amendments changed

The SEC adopted significant amendments to Rule 10b5-1 in December 2022, largely because the original rule was being used opportunistically — plans adopted and cancelled around known events, or single-trade plans set up days before good news.

The main additions:

• Cooling-off periods. Directors and officers must generally wait a set period between adopting a plan and its first trade — tied to the later of 90 days, or two business days after the company files the financial results for the quarter in which the plan was adopted, capped at 120 days. Other employees face a shorter cooling-off period.
• Officer and director certifications. They must certify at adoption that they are not aware of material non-public information.
• Limits on overlapping plans, and a restriction on multiple single-trade plans within a 12-month period.
• A good-faith requirement that operates for the life of the plan, not just at adoption.
• Disclosure. Companies must disclose the adoption and termination of director and officer plans in their quarterly reports, and Form 4 now includes a checkbox indicating whether a reported transaction was made under a 10b5-1(c) plan, with an optional footnote for the adoption date.

For anyone reading insider data, that last one is the practical payoff: since these rules took effect, the filing itself usually tells you whether a trade was planned.

How to read it on the filing

1. Find the 10b5-1 checkbox near the top of the Form 4. If it is ticked, the transaction executed under a plan.
2. Read the footnotes. Where the adoption date is disclosed, you can measure the gap between decision and execution. A plan adopted 11 months ago tells you about last year.
3. Check whether the box is absent, not just unticked. Filings made before the amendments took effect, and some filings by non-officers, may disclose plan status only in a footnote — or not at all.
4. Compare against the price chart. A discretionary buy into a sharp drawdown is the strongest version of the signal. A plan buy at the same moment is a scheduling artefact.

Does a plan purchase mean nothing?

No — and this is where people overcorrect.

Adopting a plan to buy stock is itself a decision, and a fairly unusual one. Most 10b5-1 plans are selling plans: executives use them to diversify a concentrated position on a schedule. An insider who sets up a plan to systematically accumulate more shares in a company they already have enormous exposure to has expressed a real view — just at adoption, not at execution.

So the honest ranking is:

1. Discretionary open-market purchase (code P, no plan) — the strongest signal, especially into weakness, and especially clustered.
2. Purchase under a plan adopted recently — real, but dated.
3. Purchase under a long-running plan — mostly noise for timing purposes.
4. Grants, option exercises and tax withholding (codes A, M, F) — not buying at all. See the full code reference.

Putting it to work

When a cluster shows up on the screener, the follow-up question is always the same: did these people decide, or did a calendar decide for them? Open the underlying filings from the company dashboard, check the plan checkbox on each, and discount accordingly. A four-insider cluster where three purchases are plan-driven is really a one-insider signal.

It is a two-minute check that removes a meaningful share of false positives.

Frequently asked questions

What is a Rule 10b5-1 plan? A written plan an insider adopts, while not in possession of material non-public information, that pre-specifies future trades. Trades executed under it get an affirmative defence against insider-trading liability.

Can I tell from a Form 4 whether a trade was pre-planned? Usually yes. Form 4 carries a checkbox indicating the transaction was made under a 10b5-1(c) plan, and footnotes may disclose the adoption date.

Are 10b5-1 purchases bullish? Less so than spontaneous ones. The decision was made when the plan was adopted, so the purchase reflects the insider's view at that earlier date, not on the day it executed.

Why did the SEC change the rule in 2022? To curb opportunistic use — plans adopted or cancelled around known events, and single-trade plans placed just before announcements. The amendments added cooling-off periods, certifications, disclosure requirements and limits on overlapping plans.