Racer Systems GmbH & Co. KG
The Racer Systems GmbH & Co. KG develops and licenses RacerPro for commercial applications. RacerPro is the semantic middleware for industrial projects based on RDF/OWL, a W3C standard.
http://www.racer-systems.com/
The Pellet OWL Reasoner
One of the most popular description logics reasoner.
http://www.mindswap.org/2003/pellet/