Insiders Trades Sigma vs OpenInsider
OpenInsider offers a focused view of US SEC Form 4 filings. Sigma adds available public records from 43 configured markets, entity histories, a composite ranking, public backtest evidence, REST API and MCP. Coverage, latency and field completeness vary by source.
Market coverage
OpenInsider focuses on US SEC Form 4 records. Sigma also indexes available records from AMF BDIF, BaFin, SIX SER, RNS and other configured sources. Local filing rules differ, so Sigma preserves source links and exposes missing fields instead of claiming every record is equivalent.
Scoring and backtest
OpenInsider supports direct screening of Form 4 rows. Sigma adds a 0-to-100 composite score built from available transaction, role, cluster, track-record and market fields. Missing inputs add no evidence. The methodology and priced historical subsets are public, with drawdowns, losing periods, overlap and point-in-time limits disclosed.
API and MCP: what OpenInsider doesn't have
OpenInsider does not publish an official API. Sigma exposes documented REST and MCP interfaces under plan-specific quotas. Responses retain source identifiers and null fields. Production users should still reconcile important rows with the original filing and handle delayed, corrected or incomplete source data.
When to prefer OpenInsider
Choose OpenInsider for a focused, free US Form 4 table. Choose Sigma when you need European entity pages, ranked research signals, explicit backtest caveats, or documented REST and MCP access. Verify coverage for each regulator before relying on either workflow.
One-line verdict
OpenInsider is a focused US Form 4 screener. Sigma is a broader research and data workflow whose coverage and evidence limits remain visible.