Our Firm History

Founded in 1921

The history of Olsen Thielen CPAs begins in England with a man named Tom Macoubrey.  Born in 1894, Macoubrey came to America as a young man and worked for one of the Midwest’s earliest telephone companies before it was bought out by Northwestern Bell.  With his connections in the telephone industry, Macoubrey used his natural talent for numbers to establish an accounting firm in St. Paul in 1921, T.C. Macoubrey and Company.

The Early Years

From its earliest years, Olsen Thielen has served clients in what is now known as the telecommunications industry. Macoubrey was instrumental in forming the first telephone holding company in Minnesota as well as the Minnesota Telephone Association. But Olsen Thielen also has strong ties to the health care industry, beginning with Macoubrey’s participation in the formation of Blue Cross of Minnesota. Other notable clients included Red Wing Shoes, Northwest Plastics and Weyand Furniture Co., denoting our roots in manufacturing.

Reynold Thielen & Robert Olsen

Reynold Thielen became an employee in 1953, almost one year after meeting Macoubrey at his mother-in-law’s funeral. His future partner, Robert (Bob) Olsen, joined the firm in 1954 after assisting the company with monthly statements for a new client and taking over all certified audits.  Within three years, Macoubrey decided to retire, and asked Olsen and Thielen to buy him out.   At the time that Olsen and Thielen became members of the firm, total annual collections were $57,000.  They often traveled to client offices, putting in as many as 85-90 hours per week during the busy tax season.

Key Industries & Services

Business growth stemming primarily from the telephone industry, health care, waste haulers and real estate resulted in Olsen Thielen’s relocation in 1971 to a facility in Little Canada. In the early 1980s, Olsen Thielen expanded to serve clients in the Minneapolis area, and now have an additional office in Eden Prairie.  Reynold Thielen retired in 1984 and Bob Olsen retired in 1995.  In 2008 the firm had outgrown the Little Canada facility and relocated to their current location in the Roseville area. Over the past years, the firm has met client needs for specialized services, developing expertise in utility consulting, benefit plan consulting and administration, business valuations, financial planning and IT consulting.

Today, Olsen Thielen is one of the top 25 and largest CPA firms in Minnesota, with 18 principals and over 104 staff. Our team members are experts in the individual and corporate tax, assurance, financial planning, business consulting and technology fields, backed by a proud history of trusted client relationships in the Upper Midwest.

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