Claes has worked both at court and with Sweden’s largest law-firm. Through working as a notary and fiscal clerk at court and as an associate lawyer, he acquired experience and knowledge of general commercial law matters as well as commercial legal disputes. He also has a broad knowledge base across a range of legal fields as a result of serving as a judge and working as a lawyer. Claes regularly serves as counsel in large-scale arbitration cases and sizeable judicial legal disputes; he also serves as an arbitrator in arbitration cases. Within the fields of construction law and consulting law, Claes is involved in ongoing counselling for the employer side as well as the contractor side. His work for the law firm also involves property transactions, agreements within the fields of property law and construction law and public procurement.