İstanbul Deniz Otobüsleri Sanayi ve Ticaret A.Ş. (İDO – İstanbul Sea Bus Corporation) was founded by İstanbul Metropolitan Municipality in 1987 to increase the share of sea transport in commuter traffic in İstanbul. It now boasts one of the largest passenger ship fleets in the world. Acquisition of İDO took place on June the 16th 2011 by TASS Denizcilik ve Ulaştırma Hizmetleri A.Ş. (TASS), owned by Tepe İnşaat in partnership with Akfen Holding, Souter Investments and Sera Gayrimenkul.