investors fled the civil war, Liberia's wartime economy featured the exploitation of the region's diamond wealth. The country acted as a major trader in Sierra Leonian blood diamonds, exporting over US$300 million in diamonds in 1999. This led to a United Nations ban on Liberian diamond exports in 2001, which was lifted in 2007 following Liberia's accession to the Kimberley Process Certification Scheme. In 2003, additional UN sanctions were placed on Liberian timber exports, which had risen from US$5 million in 1997 to over US$100 million in 2002 and were believed to be funding rebels in Sierra Leone. These sanctions were lifted in 2006. Due in large part to foreign aid and investment inflow following the end of the war, Liberia maintains a large account deficit, which peaked at nearly 60% in 2008. Liberia gained observer status with the World Trade Organization in 2010 and is in the process of acquiring full member status.
Liberia has the highest ratio of foreign direct investment to GDP in the world, with US$16 billion in investment since 2006. Following the inauguration of the Sirleaf administration in 2006, the country signed several multi-billion dollar concession agreements in the iron ore and palm oil industries with numerous multinational corporations, including BHP Billiton, ArcelorMittal, and Sime Darby. The Firestone Tire and Rubber Company has operated the world's largest rubber plantation in Liberia since 1926. Liberia has also begun exploration for offshore oil; unproven oil reserves may be in excess of one billion barrels. The government divided its offshore waters into 17 blocks and began auctioning off exploration licenses for the blocks in 2004, with further auctions in 2007 and 2009. An additional 13 ultra-deep offshore blocks were demarcated in 2011 and planned for auction. Among the companies to have won licenses are Repsol, Chevron, Anadarko and Woodside Petroleum.
Due to its status as a flag of convenience, the country has
