Company played an important role (as well as Knauf) in the reconstruction of destroyed and occupied Mariupol. Investigators found concrete blocks wrapped in green film with the inscription WKB Systems GmbH on them at numerous construction sites. The company, among other things, equips plants for concrete block production. The company's main shareholder is Russian oligarch Viktor Budarin, who used his German company as a supplier to the construction industry in Russia. He is not subject to any sanctions. Customs data reviewed by journalists revealed that WKB Systems had supplied complete plants for aerated concrete block factories for several years to one of Budarin's Russian companies – apparently, the same company whose products Russia is using in Mariupol.