Misc, a wholly owned subsidiary of AET, has signed a contract to buy four very large crude carriers (VLCCs) from Daewoo Shipbuilding and Marine Engineering for $436m.
Each 20,000dwt ship will cost Misc $105m-$110m, the company said.
AET is planning to build a fleet of 150 tankers, including VLCCs and medium-range product tankers, to expand its lightering business in the US.
Lightering involves the transfer of cargo between ships of different sizes to facilitate the berthing of large ocean-going vessels at shallow ports.
The shipbuilder will deliver the tankers between December 2012 and October 2013.