erdman started a construction company in 1946, which he incorporated in 1951 as marshall erdman & associates. an integrated healthcare design-build company, marshall erdman & associates grew rapidly, expanding into six different markets throughout the u.s. in early 2008, marshall erdman & associates was purchased by cogdell spencer, a healthcare real estate investment trust, for $247 million. this part of marshall's legacy is now traded on the nyse as csa.