About Overseas Shipholding Group, Inc. Overseas Shipholding Group, Inc. is a publicly traded company providing liquid bulk transportation services for crude oil and petroleum products in the U.S. Flag markets. OSG's U.S. Flag fleet consists of Suezmax crude oil tankers, conventional and lightering ATBs, shuttle and conventional MR tankers, and non-Jones Act MR tankers that participate in the U.S. Tanker Security Program.