An insider cluster buy is three or more insiders buying the same stock in a short window. It is the strongest pattern in Form 4 data, and almost no tool flags it automatically. Most screeners show you every insider trade ever filed, which is the opposite of helpful when you are hunting one specific pattern. These five get you closest.
- InsiderPulse (stockspro24.com): built for this: flags 3+ insiders buying one ticker. 5 free alerts a month, $9/mo unlimited.
- OpenInsider: no auto-flag, but its purchase screener lets you spot clusters by hand in minutes.
- InsiderScreener: unusual-activity detection surfaces stocks with abnormal insider flow.
- Fintel: insider transaction pages show every buy together, so multi-insider weeks stand out.
- Quiver Quantitative: insider datasets with clustering-friendly filters for the quant-minded.
Sources: [OpenInsider](http://openinsider.com/)
Automation is rare in this corner. If you want the flag without the homework, use the tool built for it.