Best Free Regulatory Filings Monitoring Tools for Investors

Find and update company information (Companies House)

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Companies House Find and update company information is the official free UK company register for searching companies, filings, officers, ownership-control records, and document images. Use it for UK due diligence, private-company checks, filing alerts, and developer workflows that need primary-source registry data rather than analyst commentary.

FOIAsearch

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FOIAsearch is a free SEC FOIA log search and alert product for investors, journalists, short sellers, and investor-relations teams watching for regulatory or reporter attention around public companies. It is strongest as an early-warning research signal: SEC FOIA requests, B7A exemption denials, portfolio alerts, IR Watch, and prominent-reporter alerts can prompt deeper due diligence before a story or enforcement signal becomes widely visible. The output is indirect evidence, not proof of wrongdoing, and paid alert pricing is not publicly listed in the local profile.

Insider Monitor

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Insider Monitor is a free U.S. insider-trading reference site for tracking SEC Forms 3, 4, and 5 across insider purchases, sales, officer cluster buys, and top insider-buying lists. It is useful as a quick, no-login way to spot recent Form 4 activity and then jump back to the original SEC filing. Because insiders can report trades after the transaction date and the site does not advertise alerts, exports, or an API, it should be treated as a lightweight research prompt rather than a complete monitoring system.

Open Payments (CMS)

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Open Payments (CMS) is the official free U.S. database for Sunshine Act payment, research, and ownership disclosures between drug or device companies, GPOs, and covered healthcare providers. Use it for healthcare investing, policy, compliance, and key-opinion-leader research when you need source-level evidence of manufacturer-provider relationships.

OpenCorporates

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OpenCorporates is a large legal-entity and company registry database for researchers, investigators, data teams, KYC workflows, ownership mapping, and corporate transparency work. It has substantial branded demand and commercial API interest, but its value is entity identity, provenance, registry links, officer records, relationships, and bulk data rather than stock-market analytics. Free and open-data access is license-limited, while commercial API and bulk SFTP datasets require paid plans. It is not a valuation platform, market-data feed, company fundamentals terminal, broker, or portfolio research product.

PCAOB AuditorSearch

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PCAOB AuditorSearch is the official free lookup for the audit firms and engagement partners behind U.S. public-company audit reports. It is useful when governance, audit-quality, restatement, or auditor-change work needs source-level audit provenance rather than another market-data estimate.

SEDAR+ (CSA Public Filings - Canada)

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SEDAR+ is the official Canadian Securities Administrators public-filings system for Canadian issuer and investment-fund disclosure. It is useful when investors need primary-source Canadian filings, prospectuses, reporting-issuer status, cease-trade orders, or disciplined-list checks, but it is not a global filings terminal, broker, ticker-first screener, or public data API.

SentiSense

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SentiSense is a beta AI market-intelligence and data API platform for investors and developers who want stock data, sentiment, news clustering, social signals, institutional flows, insider trades, congressional trading disclosures, and AI-generated insights in one workflow. Search demand is small but commercially relevant around AI market intelligence and news sentiment APIs, so the copy should be precise about beta status, quota limits, and PRO-gated datasets. Use it as a signal layer for research, not as a broker or adviser.

Special Situations Digest

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Special Situations Digest is a weekly global event-driven research workflow for investors sourcing activist campaigns, strategic reviews, spin-offs, going-private deals, divestitures, tender offers, restructurings, and M&A across 30+ countries. It is built for fast idea generation and triage, with structured situation cards, a searchable database, spreadsheet/PDF/JSON exports, Copy-for-LLM, and a real-time EDGAR/OTC live feed. It is not a full diligence replacement, valuation modeler, broker, or personalized investment-advice service.

This Is Not SEDAR

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This Is Not SEDAR is an unofficial, beta-stage convenience layer for browsing Canadian SEDAR+ filings through a simpler latest-filings interface and mirrored PDFs. It can help with quick Canadian filing discovery, but official SEDAR+ remains the source of record, and the site has migration, reliability, API, and SLA limitations.

SEC API (sec-api.io)

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SEC API is a commercial SEC/EDGAR API suite for developers, quants, compliance teams, and AI products that need fast filing search, real-time feeds, XBRL-to-JSON conversion, section extraction, insider filings, 13F data, and other structured regulatory datasets. It is strongest when you want production-ready normalized SEC data instead of building your own EDGAR ingestion stack, but the free tier is only a small starter allowance and redistribution requires enterprise terms.