The storm ransomware group listed Otto Sieve GmbH on its data leak site on 2026-08-27. Country: DE Sector: Manufacturing Claim as published on the leak site: Otto Sieve GmbH is a family-owned German company specializing in building services and modern home technology. Founded in 1967, the company provides heating, ventilation, sanitary, solar, and renewable energy solutions. Its services cover the planning, installation, maintenance, repair, and modernization of heating systems, bathrooms, heat pumps, solar technology, ventilation, and related building systems. Otto Sieve serves customers involved in new construction, renovation, and modernization projects and also provides maintenance and emergency repair services. The company emphasizes energy-efficient, sustainable solutions, technical expertise, personal consultation, and high-quality workmanship. Its headquarters is in Lohne, Lower Saxony, Germany. The company headquarters is located in Lindenstraße 102a, 49393 Lohne, Germany. 11-50 Employees