In 1991, he founded IOTA Inc, a private technology research company which worked with major universities and government agencies on a range of communications and other technologies, securing a number of patents. Defries worked with Oxford University Communications Engineering Department and leading UK optical / photonic companies and research groups on the design and development of optical wireless technology. In 2000 he lost US$22 million in an offshore tax evasion scheme. In 2005 Defries founded Matter Inc, a Caltech/Stanford startup for plasmonic research and development with scientists from Stanford, California Institute of Technology and New York University to work on materials science, nanophotonics and energy related projects. In 1975, Tony's long-term girlfriend, Melanie McDonald, gave birth to his oldest daughter, Fleur Dominique Defries. Tony married Marlene Weir in London, in 1986, and their daughter Tatiana Alexandra Defries was born in 1988.