

The earlier flag has a black-white-red-black striped field with a white diamond outlined in black, bearing K.I.A. above two crossed black hammers. The 1955 name change brought a change of livery.
Brown 1982 shows a white flag with a black diamond containing a white circle. A narrow white band extends from the circle to the field; the circle bears black VC. Rosanoski relates this to the Veba-Chemie name recorded by the late 1970s.
The company originated in Königsberg on 17 April 1899 as Kohlenimport- und Steinkohlenbrikettfabrik A.G., founded by August Schwanfelder and Hans Rosenkranz. Schwanfelder left in 1909. Hugo Stinnes joined in 1919 and took over in 1920, when Rosenkranz left. Coal-importing developed into shipowning in the 1920s, with a Memel branch transporting coal for Stinnes’s factories; that branch closed five years later for unknown reasons. Frachtcontor held 40% from 1920 until the 1925 merger.
As Kohlen-Import A.G. (K.I.A.G.), it took over a tug from Hugo Stinnes and Joseph Abelmann. Poseidon GmbH and Artus barge companies were also formed as Koholyt A.G. subsidiaries. The fleet expanded following permission in 1921 to buy back what the source calls wartime “rehabilitations”. Consolidation in 1924 brought the name Kohlen-Import & Königsberger Reederei. After Stinnes’s death and the group’s collapse, the ships were placed under Reederei Kohlen-Import & Poseidon-Schiffahrs A.G. Königsberg on 24 July 1925. Existing names were retained, with later ships named after geographical landmarks.
War forced a move to Nordenham in 1944 and then Hamburg. The Stinnes family subsequently left the A.G. but retained KIA/Poseidon and Midgard Reederei. Associated-company ships were managed with Fritz Ivers as freight forwarder. F. Ivers & Co., founded in Stettin on 10 December 1931, moved to Lübeck in 1945 and managed the Baltic ships. A later subsidiary note prints the move as 1845. For Transbaltica, F. Ivers was the correspondence shipowner; Cosima-Poseidon Schiffahrt GmbH acted for the Cosima shipowners. This tax-saving company had never belonged to Hugo Stinnes A.G. and had its own flag and funnel.
The 1955 name was Poseidon Schiffahrts GmbH. Later names included Veba-Chemie Poseidon Tankschiff GmbH and Veba Poseidon Schiffahrt GmbH, owned 60% by Veba Oel and 40% by Stinnes Reederei. Lloyds gives inconsistent formation dates of 1926 and 1996 for these later identities. Rosanoski tentatively connects the return to Poseidon Schiffahrt GmbH with the sale of Stinnes holdings from 1999. Also known as Poseidon Lines, it ceased shipowning during the 1970s–1980s, chartered through Frachtcontor Junge & Co., and from 2002 acted only as commercial tanker manager. A 50% Frachtcontor interest acquired in 1972 was transferred to the Stinnes Group in 1991; France Shipmanagement managed part of the fleet in the 1998 account.
Germany, Königsberg; Hamburg from 1945.