Like computer companies at the time and unlike manufacturers of IBM PC compatibles, Apollo produced much of its own hardware and software.[citation needed] The founding engineering team included Mike Sporer, Bernie Stumpf, Russ Barbour, Paul Leach, and Andy Marcuvitz.Apollo workstations ran Aegis (later replaced by Domain/OS), a proprietary operating system with a Unix alternative shell.[citation needed] Apollo's largest customers were Mentor Graphics (electronic design), General Motors, Ford, Chrysler, Chicago Research and Trading (Options and Futures) and Boeing.It used the concepts of shell programming (à la Stephen Bourne), single-level store, and object-oriented design.Thomas Vanderslice was hired as President and CEO in 1984,[11] and founder William Poduska left the company in 1985 to found Stellar.[12] The company incurred large losses in 1987 in currency speculation due to the trading activities of one individual,[13] and in 1988 from declining demand for its products.