WASHINGTON -- The Supreme Court ruled Tuesday that corporations have no right of personal privacy to prevent the disclosure of documents under the federal Freedom of Information Act.

Chief Justice John Roberts wrote the 8-0 opinion Tuesday that reversed an appeals court ruling in favor of AT&T. The outcome was notable for its unanimity, especially in view of recent criticism from liberal interest groups that the court tilts too far in favor of business.

"The protection in FOIA against disclosure of law enforcement information on the ground that it would constitute an unwarranted invasion of personal privacy does not extend to corporations," Roberts wrote. "We trust that AT&T will not take it personally."

At issue is information gathered by the Federal Communications Commission during an investigation of AT&T's participation in the federal E-Rate program, which helps schools and libraries get Internet access. In December 2004, The telecommunications giant paid $500,000, but admitted no wrongdoing, to resolve allegations that it overcharged the government.

Several months later, COMPTEL, a trade group representing some AT&T competitors, sought documents that the FCC obtained in its investigation. AT&T said all the information should remain secret.

The federal appeals court in Philadelphia agreed with AT&T, but not a single justice did.

Last year, the justices were sharply divided in a decision over the rights of corporations, freeing businesses and unions to spend unlimited sums to influence federal elections.

This case, though, turned more on dictionary definitions and practical word usages.

"Adjectives typically reflect the meaning of corresponding nouns, but not always," Roberts said. Thus, even though Congress included corporations in the noun "person" in the FOIA, it does not necessarily follow that "personal" also would apply to them, Roberts said.

The word "crab" can refer to "a crustacean and a type of apple," he said. But "crabbed" often is used to describe handwriting that is difficult to read, Roberts said.

The decision does not leave corporations totally defenseless under FOIA. Other provisions of the law protect against the release of trade secrets and information that allows people to be personally identified.

In the AT&T case, the FCC had released some of the information under an open records request, but withheld other documents because of concerns that business secrets or humans' privacy might be compromised.

Justice Elena Kagan, who worked on the dispute when she was at the Justice Department, did not take part in the case.

The case is FCC v. AT&T, 09-1279.