Dr. Werner Diez was born in Ulm/Donau on March 3, 1929 and attended high school in Schorndorf from 1939 to 1948. Afterwards he studied economics at the University of Tübingen, during which time he gained practical experience in various industrial companies, a bank and a trust office. He passed his diploma examination in 1951 and completed his studies with a diploma thesis entitled "Ertragswert bei der Gesamtbewertung von Unternehmungen". This was followed by employment as a tax administrator and auditor with two auditing companies in Stuttgart.

Dr. Diez received his doctorate in July 1953 from Prof. Dr. Rudolf Johns with a dissertation on "Principles of the overall valuation of companies and company shares in business administration and tax law". He was admitted as a tax advisor in 1958, as a certified public accountant in 1961 and as a legal advisor in commercial and corporate law in 1970.

From 1961-1971, Dr. Werner Diez was a shareholder-managing director of an auditing and tax consulting company. He then set up his own auditing and tax consultancy company in Stuttgart. This company focused on providing comprehensive consulting services to medium-sized companies, including those with international operations, and he managed it together with a partner until 1991. In the same year, the company was converted into a limited liability company (GmbH) and subsequently sold to one of the five largest auditing firms.

From 1981-1991, Dr. Diez also organized seminars for companies on special issues of business administration, tax, commercial and corporate law and was a member of various supervisory, administrative and advisory boards, mainly of family businesses.

Dr. Diez continues his advisory board activities in the form of an individual practice and has also advised companies on tax, organizational and, in particular, succession issues as well as on corporate law.

On Sunday, May 29, 2011, Dr. Werner Diez passed away at the age of 82.