The Casey Mahon Files series originates from the University of Iowa's Finance and University Services (FUS) department and represents the bulk of the collection. Material in the series principally documents Mahon's involvement in the committee and broader conversation about the University of Iowa’s disinvestment from companies operating in South Africa.

There are several notable subgroupings in the series. The first two are “Divestment correspondence file” and “Company Files”. The former consists of community members writing to university administrators, typically University President James Freedman, to express their feelings about divestment; the latter is a series of topical files that documents the efforts of Mahon and Dorsey D. Ellis Jr., FUS vice president, to learn more about each company’s involvement in Apartheid South Africa.

The final major grouping in the series, “Divestment literature”, consists of reference material about divestment that does not specifically focus on the University of Iowa or its community.