Piet Jan Heijboer

Croonwolter&dros BV operates as an engineering company with activities in the industrial, infrastructure, and utility sectors. It offers asset management, automation, geothermal, maintenance, system integration, tunnel design, tunnel maintenance, inspection, safety, revitalizing, and security services. The company was founded by Hendrik Jan Wolter in 1875 and is headquartered in Rotterdam, the Netherlands.

TBI Holdings BV operates as a financial holding company with activities in the engineering, construction and development, and infrastructure industries. Its subsidiaries include Comfort Partners, Croon Elektrotechniek, Eekels Technology, Era Contour, Groothuis Wonen, Hazenberg Bouw, Hevo, J.P. van Eesteren, Koopmans Bouwgroep, MDB, Mobilis, Nico de Bont, Synchroon, Timmermans Infratechniek, Voorbij Funderingstechniek, Voorbij Prefab, Wolter and Dros, and WTH Vloerverwarming. The company was founded in 1981 and is headquartered in Rotterdam, the Netherlands.