Welcome to MuckRock's Freedom of Information Act appeal guide!

Each entry provides background and context about an exemption to the public records laws in all fifty states, as well as federal FOIA. Read more about United States of America's public records law or explore all our expert FOIA guides. Have a public records appeal or information on an exemption we should include? Consider sharing your knowledge with everyone by donating your FOIA appeal language.


Also known as Trade secrets, 5 U.S.C. § 552(b)(4), b4.

This guide is for informational purposes only, is general in nature, and is not legal opinion nor legal advice regarding any specific issue or factual circumstance.

5 U.S.C. § 552(b)(3) states that “trade secrets and commercial or financial information obtained from a person and privileged or confidential.”

What it means: Trade secrets and other confidential or privileged commercial or financial information.

What it really means: “The business of America is business.”

What you can do about it: The nice thing about b(4) is that it typically involves corporate lawyers. And while that sounds like the set-up to a joke, corporate lawyers are refreshingly exact in what they don’t want you to see and why, as well as what recourses you have to challenge them.

Now, occasionally, you’ll run into an agency deciding on behalf of the company what they’re allowed to give you, in which case you’ll need to call up your new best friend at Weyland-Yutani Legal and let them know the FDA’s doing their job for them. FOIA makes for strange bedfellows.

Key Citations

DOJ Exemption 4 Guidance