Butte, Montana’s Best Tax & Accounting Services If you need tax & accounting services in the Butte, Montana area, visit us at Mark Rule & Company. We have the expertise, reliable customer service and quality tax & accounting services you want. Mark Rule & Company is a fully service accounting firm, specializing in tax preparation for individuals and businesses. We have been in business for over 30 years in the Butte, Montana area. We primarily serve southwestern Montana, but have clients all over the United States.