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Understanding SEC Exhibit 21 and why corporate subsidiary disclosure matters

What is Exhibit 21?

Exhibit 21 is a required attachment to the annual 10-K report that every U.S. public company files with the Securities and Exchange Commission (SEC). It lists all subsidiaries that are "significant" to the company—typically wholly owned or majority-owned entities.

The SEC mandates this disclosure under Regulation S-K. Companies must include the legal name and jurisdiction (state or country) of incorporation for each subsidiary. This creates a public record of where companies have structured their operations, holdings, and intellectual property.

Exhibit 21 is often buried in the appendices of lengthy 10-K filings. We parse this data, make it searchable, and visualize it so you can explore corporate structures without digging through hundreds of pages of legalese.

Regulation S-K (17 CFR Part 229)

Why This Matters

Transparency and accountability

Subsidiary disclosure allows investors, researchers, and the public to see where companies operate. It reveals holding structures, offshore entities, and geographic diversification—data that was historically difficult to access and analyze at scale.

Tax havens and low-tax jurisdictions

Many subsidiaries are incorporated in jurisdictions known for low or zero corporate taxes: Cayman Islands, Ireland, Luxembourg, Delaware, and Singapore, among others. A high concentration in these locations can indicate aggressive tax planning. Our jurisdiction analysis classifies subsidiaries by tax haven tier (high-risk, moderate, or standard) based on the EU blacklist, Tax Justice Network, and OECD data.

What we don't do

We present the data as reported. We do not provide legal, tax, or investment advice. The presence of subsidiaries in low-tax jurisdictions does not necessarily indicate wrongdoing—it may reflect legitimate business needs. Our goal is to make the data accessible so you can draw your own conclusions.

Tax Haven Classification

High-risk tax havens

Zero or near-zero corporate tax, high secrecy. Examples: Cayman Islands, Bermuda, British Virgin Islands, Luxembourg (for certain structures), Jersey, Panama.

Moderate / low-tax jurisdictions

Low rates or favorable structures. Examples: Ireland, Singapore, Hong Kong, Delaware, Nevada, Switzerland, Netherlands.

Standard jurisdictions

Normal corporate tax regimes. Most U.S. states and countries fall into this category.