Siegfried Nottbohm

BTG Beteiligungsgesellschaft Hamburg mbH is a regional private equity firm established in 1970 and located in Hamburg in northern Germany. BTG's shareholders and investors are banks, including international banking groups based in Germany and local savings banks. The chief purpose of BTG is to foster regional economic development, and to maintain and develop employment opportunities in and around Hamburg.

Part of D+H Mechatronic AG, D+H Deutschland GmbH is a German company that specializes in trend-setting bus communication. The company is based in Ammersbek, Germany. The company offers AdComNet and ACB, which are efficient communication networks for complex SHEV and ventilation scenarios. The CEOs of the company are Thomas Rößler, Friedrich-Wilhelm Reckfort, Dirk Dingfelder.

D+H Mechatronic AG specializes in smoke extraction and ventilation solutions. The company is based in Ammersbek, Germany and has subsidiaries in Germany. The German company's expertise ranges from natural ventilation to mechanical smoke extraction. The CEO of the private company is Dirk Dingfelder.