The idea
One insider buying shares can be a personal decision. When the CEO, the CFO and two directors all buy within a few weeks, it is harder to explain away. That pattern is called a cluster buy. Investors watch for it because it suggests several people with inside knowledge reached the same conclusion on their own.
How WallStPal defines it
A stock appears on our cluster buys list when at least two different insiders each reported at least $10,000 of open-market purchases (code P) within 30 days. We also show a separate list for 31 to 90 days ago. The list is ranked by the total amount bought.
The $10,000 floor is there for a reason. Some companies run employee purchase programs where dozens of officers buy a few shares on the same day. Without a floor, those programs would fill the list with clusters that carry no information.
What to check
- Who is buying. Purchases by the CEO and CFO usually carry more weight than purchases by outside directors.
- How much, compared with what they already own. Doubling a holding means more than adding 1%.
- Timing. Buys right after bad news or a sharp drop are common. Buys alongside a stock offering may be meant to support the deal.
- Company size. At very small companies, insiders often buy small amounts to signal confidence. Check the dollar figures.
Examples
A cluster in the October 2026 data. In the weeks to mid-October 2026, Ryan Cohen, GameStop’s CEO, and another GameStop insider, Nat Turner, both reported open-market purchases, about $50.7 million combined according to their Form 4 filings. Two insiders, both buying meaningful amounts within a month: that is the pattern the list is built to catch. Whether it turns out well is a separate question, which is why each stock page shows how the shares moved after past purchases.
An employee purchase plan. Also in October 2026, about 30 officers of one large company each reported buying a few thousand dollars of stock on the same day, the pattern of a regular purchase program. Ranked by the number of insiders, it would top any cluster list. Ranked by dollars per insider, it disappears. That is why we use a minimum per insider.
Explain it like I’m 13
Suppose one teacher at your school buys a ticket to the school play. Maybe they just like plays. Now suppose the principal, the drama teacher and three other teachers all buy tickets the same week, with their own money. They have all seen rehearsals. You would start to think the play is going to be really good.
A cluster buy is the same thing with a company’s stock: several people who know the company well all buying at about the same time.
A caution
Clusters are a pattern in the filings, not a promise. Insiders can be wrong together, especially in a struggling industry. Use a cluster as a reason to read the company’s filings, not as a trade.
Questions about this guide? Pal reads it with you and answers in plain English.
WallStPal explains public filings. Nothing here is investment advice. Editorial policy · Corrections