029 Group SE is an investment holding company that operates an investment platform focused on real estate, hospitality, and lifestyle sectors in Germany. Its platform includes aethos.com, a European collection of hotels and clubs; eterniti.com, emeraldstay.com, and bo-house.com, a B-Corp vacation rental operator; and myne-homes.com, a co-ownership platform for luxury vacation homes. The company also invests in and develops land projects, invests in nursing living properties, and develops residential land. It operates under the Limestone Capital, Periskop, HotelBird, Brother's Bond, and fjör brands. Formerly known as Mendarion SE, it changed its name to 029 Group SE in August 2022, was incorporated in 2018, and is based in Berlin, Germany.