About ClusterDesk

What is a cluster buy?

A cluster buy occurs when two or more insiders at the same company purchase shares in the open market within a 5-trading-day window. This pattern is considered a stronger signal than a single insider buying, because it suggests independent conviction across multiple people with inside knowledge of the company.

Our methodology

• Source: SEC Form 4 filings via OpenInsider
• Universe: U.S. micro-cap stocks ($50M – $500M market cap)
• Open market purchases only (transaction code P)
• Minimum $25,000 per insider, $100,000 combined cluster value
• Excludes: 10b5-1 plans, RSU vesting, option exercises, ESPPs
• Scored 0–100 on cluster size, value, seniority, and recency
• Only clusters scoring 60+ are published

Scoring

Each cluster is scored on four dimensions: number of insiders (up to 30 pts), total purchase value as a percentage of market cap (up to 25 pts), seniority of roles — CEOs and CFOs score higher than Directors (up to 25 pts), and how tightly clustered the trades are in time (up to 10 pts), plus trade size (up to 10 pts). Maximum score is 100.