In 1981, McAuto began processing medical claims after it acquired Bradford Systems and Administrative Services for $11.5 million. In 1983 two principals of Bradford who had to come work at McAuto left to form the Sanus Corporation health maintenance organization. The St. Louis office of Sanus was wholly owned by McDonnell Douglas. McDonnell Douglas personnel including Joseph T. Lynaugh and Howard L. Waltman formed Sanus in 1983. In 1986 after McDonnell Douglas reduced its control, Sanus announced a partnership with St. Louis pharmacy Medicare Glaser to form Express Scripts with the pharmacy providing drugs for the Sanus HMO. Charles H. Ridings, formerly in charge of McDonnell Douglas mergers and acquisitions, was named the first chief executive (although he was quickly replaced by Waltman). The new company soon abandoned the HMO business to become with the country's largest independent pharmacy benefit management organization and became the 22nd largest company in the U.S. in 2017 with revenue exceeding $100 billion—making it far larger than McDonnell Douglas. Five new Express Scripts buildings now sit on the east side of Lambert Airport along I-70.