Clark, Schaefer, Hackett & Co. is an Ohio-based accounting and consulting firm with six offices spread throughout the Buckeye State. The company's services include tax, assurance, qualified plan design, administration and auditing, litigation support, internal audit, outsourcing, business transactions and valuations, and financial planning. 

Clark, Schaefer, Hackett & Co. has its roots firmly in Ohio soil. Virgil Clark established a small accounting practice in Middletown in 1938; it remained a one-office firm until 1961, when Clark added another location in Cincinnati. With partner Bill Schaefer at the helm the business expanded to include an office in Springfield in 1967, moving on to Columbus in 1980 and Dayton in 1983.

Schaefer stepped down in 1992, paving the way for Pete Hackett, who served as president and chairman until 2002. Neil O'Connor became president that year and took the chairmanship a year later, handing the presidency over to Tom Hazelbaker. O'Connor retired from the firm in June 2007; William Hummel, who was once named one of the best tax practitioners in the United States by Money magazine, was appointed chairman.