Form4insider filings, from the source

Analytics

Insider buy/sell ratios

Two honest ratios per trading day, computed from open-market filings only: how many buy filings per sale filing, and net dollars as a share of total dollars (+1 all buying, −1 all selling). No index overlay — that needs licensed market data.

1M3M6M1YAll data260 trading days · 18,835 buys / 37,639 sales · $2200699.52B bought / $1261.84B sold
Buy : sale filing-count ratio (1.0 = as many buys as sales)
0.02.04.06.08.006-2808-0909-2010-3112-1301-2803-1107-0908-19
Net dollars as a share of total dollars (+1 = all buying)
-1.0-0.50.00.51.006-2808-0909-2010-3112-1301-2803-1107-0908-19
Daily filing countsbuy filingssale filings
05010015020025030035006-2808-0909-2010-3112-1301-2803-1107-0908-19
Daily open-market dollarsboughtsold
$0$200000.0B$400000.0B$600000.0B$800000.0B$1000000.0B$1200000.0B$1400000.0B$1600000.0B06-2808-0909-2010-3112-1301-2803-1107-0908-19

Insiders sell for many reasons (compensation, diversification, taxes) but buy for mostly one. The count ratio typically sits well below 1.0 — its changes are the signal, not its level. Days are trading-day buckets with the 4:00 pm ET cutoff.