How to Spot a 10b5-1 Plan on Form 4: Pattern Recognition Guide

Every time a senior executive's Form 4 lands disclosing a million-dollar sale, financial Twitter responds the same way: "CEO dumps stock — bearish." In modern executive compensation, that interpretation is wrong more often than it's right. The majority of senior-officer open-market sales at large-cap public companies in the United States today run through Rule 10b5-1 trading plans — schedules that lock the trades into a pre-specified calendar weeks or months before they execute, removing discretion entirely.

Reading executive selling well means knowing which sales are pre-scheduled plan executions (uninformative) and which are discretionary view-driven trades (potentially informative). The Form 4 itself usually doesn't say the answer directly — but the pattern of filings almost always does. Here's the practical reader's guide.

What Rule 10b5-1 actually does

Rule 10b5-1, established by the SEC in 2000, gives corporate insiders a structured way to trade their company's stock without violating insider trading rules. The mechanic: an executive adopts a written trading plan during an open trading window, while not in possession of material non-public information. The plan specifies in advance the price, quantity, and timing of future trades — usually as a recurring schedule. Once the plan is adopted, the trades execute automatically through a designated broker on the specified dates, regardless of what the executive knows or doesn't know later.

The practical effect: a sale executed under a plan today reflects a decision made months earlier — not a current view on the stock. If an executive adopted a plan in January 2026 to sell 8,000 shares on the third Wednesday of each month, the May 2026 sale provides no information whatsoever about anything that happened between January and May.

SEC rules (amended in 2023) now require:

• A cooling-off period of at least 90 days between plan adoption and the first trade for officers and directors.
• Mandatory checkbox disclosure on Form 4 indicating whether the transaction was executed under a 10b5-1 plan.
• Limits on overlapping plans and single-trade plans.

The footnote check (the easy way)

The cleanest way to identify a 10b5-1 plan trade is the explicit Form 4 disclosure. Since the 2023 amendments, the Form 4 XBRL data includes a checkbox indicating plan execution, and the human-readable filing usually carries a footnote of the form: "This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on [date]."

If you see that footnote, the trade is by definition not informative as a current view. The decision was made on the plan-adoption date; today's price is irrelevant.

The complication: not every legacy filing surfaces the footnote cleanly, and not every database tags the 10b5-1 flag consistently in its API output. When the footnote is missing or ambiguous, you have to read the cadence instead.

The pattern-recognition tells

Even without an explicit footnote, plan-driven trading shows specific characteristics that discretionary trading does not. Look for these signatures:

Tell #1: Constant strike price across exercises

If the executive is exercising options (transaction code M) and selling immediately (S) on the same day, watch the option strike price. If the strike is identical across multiple exercise events spanning months, those options all came from the same grant tranche and are being unwound on a schedule. Real-world example: a senior officer exercising 8,300 options at $146.03 strike every two to four weeks for six months in a row is mechanically draining a 2017-vintage grant tranche. The strike doesn't move because the options were issued from a single award.

A discretionary trader, by contrast, would not exercise the same number of options at the same strike on a predictable cadence. They would respond to market signals — accelerating into strength or delaying into weakness.

Tell #2: Calendar regularity

10b5-1 plans typically specify trades on fixed calendar dates: every other Wednesday, the 16th of each month, or a fixed offset from quarterly earnings windows. If you sort an executive's recent Form 4 filings by date and see predictable intervals — 14 days, 30 days, 60 days, or specific weekday/date offsets — you're looking at a plan. Real discretion is lumpy. Plans are clockwork.

Tell #3: Limit-price ladder execution within a single day

Within a single trading day, a 10b5-1 plan often executes via algorithmic VWAP or TWAP (volume-weighted or time-weighted average price) algorithms. These produce Form 4 filings with many small tranches at progressively rising or falling limit prices, staggered through the day. A discretionary executive trying to maximize price would consolidate to one or two large blocks at the day's high or low. The 16-tranche ladder is the signature of algorithmic plan execution.

Tell #4: Sales into strength but no acceleration into peaks

Look at the longer arc. A 10b5-1 plan typically has a fixed share quantity per execution date, which means the seller can't accelerate when the price spikes. If you see a multi-month sale tape where the executive sold 8,000 shares per month every month — even months when the stock was up 10% or down 10% — that's a plan. A discretionary seller would have skipped the down month and doubled the up month.

Tell #5: Sale price tracks market, not opportunity

For a plan, the sale price is whatever the market gives on the scheduled day, plus the limit-price ladder. The executive can't out-time the market because they don't have discretion. Compare the realized sale prices to the stock's price chart — if the sales consistently print at the midpoint of the day's range rather than at intraday highs, that's a plan execution.

Worked examples

Two real-world cases that have been examined on the 13F Insight platform:

Paul Mahon (UTHR EVP): Form 4 filings on April 2, April 16, and May 7, 2026 — three cycles in six weeks. Each cycle exercises 8,300 options at the $146.03 strike and sells the same number of shares in the open market through 16-tranche limit-price ladders. The strike is constant, the cadence is regular, and the execution is algorithmic. Every signal lines up: this is a 10b5-1 plan running on schedule.

Ken Duda (ANET CTO): Form 4 filings on March 17 and April 17, 2026 — same 32,000-share exercise size, same $15.2625 strike (a 2015 IPO-era grant), same 16-tranche limit-price ladder selling into the same intraday window. Despite ANET stock moving ~$30 higher between the two cycles, the trade structure is identical. Same plan signature.

Both filings would look bearish to a casual reader citing the headline dollar volumes. Neither is.

When discretionary selling actually matters

The flip side: there are cases where executive sales do carry information. Look for these characteristics:

• Lumpy timing: A single large sale that breaks a multi-month silence, or an unscheduled sale that doesn't fit any prior cadence.
• No prior history: A senior officer who has never sold open-market stock before suddenly executing a large sale.
• Coincident with negative events: A sale that lands within 30-60 days of disappointing earnings, an SEC inquiry, or a strategic announcement.
• No matching exercise: A standalone S transaction without a corresponding M (exercise) — meaning the executive sold shares they already owned outright rather than exercising and selling. This is more often discretionary than plan-driven, because plans typically pair exercise with sale to fund the strike payment.

Even then, qualify carefully. A discretionary sale can be motivated by reasons unrelated to the company — estate planning, divorce, philanthropic commitment, tax-loss harvesting in a separate account. The Form 4 doesn't tell you the motive; it just tells you the shape.

Cross-checking with the broader filings

The single most useful cross-check on executive selling is the institutional 13D/G tape. If insiders are selling but a major active manager just filed a 13G crossing the 5% threshold, the institutional money is doing the opposite of the executive flow. If executive selling and 13D/G exits are aligned in the same direction, that's a stronger combined signal. You can track both streams through our activist filings feed and the smart-money insights signals, or by browsing specific stocks via stock detail pages for the holder context.

For the underlying SEC reference, the canonical text of Rule 10b5-1 and the 2023 amendments is on the SEC final rule release. For our growing library of explainers on Form 4 and 13F mechanics, browse the learn hub.