Atlantic Richfield Company (ARCO) is an American oil company with operations in the United States, Indonesia, the North Sea, and the South China Sea. It has more than 1,300 gas stations in the western part of the United States. ARCO was formed by the merger of East Coast–based Atlantic Refining and California-based Richfield Oil Corporation in 1966. A merger in 1969 brought in Sinclair Oil Corporation. It became a subsidiary of UK-based BP plc in 2000 through its BP West Coast Products LLC (BPWCP) affiliate. On August 13, 2012, it was announced that Tesoro would purchase ARCO and its refinery for $2.5 billion. However, the deal came under fire due to increasing fuel prices. Many activists urged state and federal regulators to block the sale due to concerns that it would reduce competition