Manderen BV is the investment company of the Westermoskee association and Milli Görüș. This mailbox company is based outside Amsterdam and is used as a financial vehicle to enable the building of the Westermoskee. In the early nineties, Milli Görüș foreman Kabaktepe bought the firm. Manderen BV has four shareholders: the mosque associations Aya Sofya and Selimiye, and their respective youth sections.