A sales/use tax exemption was granted to a mechanical contracting/engineering firm holding a valid certificate of authority, headquartered in Missouri, for purchases of computers and computer software. The company met the exemption requirements under Missouri Regulation 144.030.2(28) which states that an exemption applies for “computers, computer software and computer security systems purchased for use by certified architectural or engineering firms headquartered in this state”. Under this regulation, “headquartered in this state” means that the office for the administrative management of at least four integrated facilities operated by the taxpayer must be located in the state of Missouri. Although this company technically performed both engineering and contracting services, (only engineering is included in the exemption), the company was found exempt from sales tax liabilities on these computer purchases because it had the four required locations. (Murphy Company Mechanical Contractors & Engineers v. Director of Revenue, Missouri Administrative Hearing Commission, No. 03-0425 RS, June 8, 2004.)