Illuminet Holdings, Inc. delivered advanced intelligent network, database and billing services to both wire line and wireless voice networks. Illuminet provided carriers access to the system of signaling networks for nearly the entire U.S. public-switched telecommunications infrastructure. The company supported telecommunications networks used to make wireless calls, long-distance calls and Internet connections by ensuring that carriers can connect to each other and also enabling advanced calling features such as caller identification and local number portability. Spectrum acted as a liquidity source to the numerous shareholders of this private company by acquiring shares in a series of negotiated transactions. Illuminet went public in 1999 and in 2001 was acquired by VeriSign, Inc. (NASDAQ:VRSN) for $1.2 billion.

Headquarters: Olympia, WA USA