In December 1981, Derry founded Larson & Company, P.A., which employs eight Certified Public Accountants and support staff.
Derry has worked in all areas of oil and gas from joint interest audits to compliance filings with all regulatory and taxing authorities. Other industries include aircraft, medical, banking, manufacturing, service organizations, and retail and wholesale trade.
Derry has assisted his clients as an expert witness in legal proceedings and in the acquisition and sale of many businesses. He is also a trustee and executor for several trusts and estates.
Derry serves as director, president and treasurer of several charitable organizations. He is also a member of the AICPA, the Kansas Society of CPA’s and the Petroleum Accountants Society of Kansas.