When Nixon closed the gold window in August 1971, the dollar lost its commodity backing. It immediately gained a new, less visible one. In 1974, Saudi Arabia agreed to price all its oil exports in U.S. dollars in exchange for American security guarantees and a Saudi commitment to recycle oil revenues into U.S. Treasury bonds. Every country that wanted oil now needed dollars. Sovereign wealth funds emerged as the warehouses of recycled petroleum money. The petrodollar system was as load-bearing for the post-Bretton-Woods financial order as gold had been for the previous one — and far less visible.