Intelligence and Information Institute

III, often called "Triple-I," is an acronym for the "Intelligence and Information Institute," a top-secret branch of United States Government, charged with dealing with the threat posed by the Transformers on Earth.

III was featured in the Marvel comics series, and Binaltech (which is a sidestory in the Animated universe).

From Teletraan I: The Transformers Wiki, a Wikia wiki.