AlphaYouWhat Is a Form 4 Filing? How to Read Insider Trading Disclosures
A plain-English guide to SEC Form 4 filings - what they are, the 2-business-day rule, and why roughly a third of insider transactions are pre-scheduled and tell you nothing about what an executive currently thinks.
A stock jumps 20% on no news you can find. A week later, you learn three different executives bought shares in the same ten-day window before it happened. That information was public the entire time, it just wasn't in front of you. That's what a Form 4 is for, and why insider trackers exist at all.
Direct answerA Form 4 is the filing a company officer, director, or 10% shareholder must submit within 2 business days of trading their own company's stock. It is the fastest insider disclosure in public markets. The catch most guides skip: a large share of those transactions are pre-scheduled under a 10b5-1 plan, meaning the executive did not decide anything on the day it happened.
- Company officers, directors, and anyone owning more than 10% of a public company's shares, collectively "insiders." Every purchase, sale, or option exercise in their own stock triggers a filing, due within 2 business days under Section 16(a).
- This is the ratio that reframes the whole category. In that same window we logged **11,544 insider sells against 3,538 insider buys**, roughly 3.3 sells for every buy, spread across 2,332 tickers on the sell side and 1,256 on the buy side.
- A 10b5-1 plan is a trading schedule an insider sets up in advance, precisely so they can trade without it looking like they acted on inside information. The trade executes on a timetable set months earlier.
Who Files, and How Fast
Company officers, directors, and anyone owning more than 10% of a public company's shares, collectively "insiders." Every purchase, sale, or option exercise in their own stock triggers a filing, due within 2 business days under Section 16(a).
Whether that deadline is met is a checkable fact rather than a promise. Across the 15,082 Form 4 events AlphaYou logged between 6 April and 22 August 2026, the median gap between the transaction and the filing landing was exactly 2 days, and 65% arrived inside the 2-business-day window. The rest were slower, which is worth knowing before you treat any single filing as fresh.
Compare that to the 45 days Congress gets and the difference is stark. Form 4 is the closest thing to a real-time insider signal in public markets.
Selling Is Normal. Buying Is the Rare Part.
This is the ratio that reframes the whole category. In that same window we logged **11,544 insider sells against 3,538 insider buys**, roughly 3.3 sells for every buy, spread across 2,332 tickers on the sell side and 1,256 on the buy side.
Insiders sell constantly and for reasons that have nothing to do with their view: taxes, diversification, a house, a divorce, scheduled compensation. Selling is the base rate. An open-market purchase, where an executive converts their own money into more exposure to a company they already depend on for income, is the genuinely unusual event. That asymmetry is why "insider buying" gets tracked and "insider selling" mostly does not.
Among the buys, directors dominate: 2,161 came from directors, against 695 from officers and 599 from 10% owners.
The Part Most Guides Skip: 10b5-1 Plans
A 10b5-1 plan is a trading schedule an insider sets up in advance, precisely so they can trade without it looking like they acted on inside information. The trade executes on a timetable set months earlier.
Of the transactions in our window where the filing indicates plan status, **about 32% were 10b5-1 plan trades**. Nearly a third of insider activity therefore reflects a decision made long before the date on the filing, and says nothing about what that executive thinks today.
If you read every Form 4 as an opinion, you will misread roughly one in three of them. The plan flag is on the filing. Check it.
How to Read One Without Getting Fooled
Look at the transaction code first: **P** for an open-market purchase, **S** for a sale, **A** for an award or grant. A lone "A" is compensation being granted, not conviction being expressed, and it moves no one's money. Then check share count, price, and total shares held afterwards, because a $50,000 buy from someone already holding $40m of stock is a rounding error in their own position.
The pattern worth noticing is a cluster: several different insiders at the same company filing P codes, not on a plan, inside a short window. One person can be wrong or idiosyncratic. Four at once is harder to explain away.
Where to See Them
SEC EDGAR publishes every filing, but it is built for compliance archiving, not for keeping up. AlphaYou turns Form 4 filings into a filterable alert feed alongside congress and 13F data, so the filing reaches you rather than you going to look for it.
FAQ
How fast must insiders disclose a trade?
Within 2 business days under Section 16(a). In our sample the median was exactly 2 days, with 65% inside the window.
Does an insider sale mean bad news?
Usually not. Sells outnumbered buys 3.3 to 1 in our sample. Selling is the base rate and happens for tax, diversification and personal reasons. A purchase is the rarer, more informative event.
What is a 10b5-1 plan and why does it matter?
A trading schedule set months in advance. Around 32% of the transactions we saw were plan trades, so they reflect a past decision rather than a current view.
Which transaction code actually matters?
P, an open-market purchase. A is a grant and reflects compensation, not conviction.
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