Saudi Arabia , the world’s biggest crude exporter, told OPEC that it cut production by 408,000 barrels a day in August, amid signs of a supply surplus that’s pushed prices to a 16-month low. The kingdom produced 9.6 million barrels a day, compared with 10 million barrels daily in July, it said in a submission to the Organization of Petroleum Exporting Countries, according to the group’s monthly oil market report today. Data collected by Bloomberg News show no bigger monthly decline since December 2012. Other estimates collated by OPEC, based on what it calls secondary sources, show the nation cut output by 55,200 barrels to 9.86 million a day. “It does illustrate a desire not to oversupply the market, and it does illustrate they are actively defending $100 a barrel,” Mike Wittner , head of oil market research at Societe Generale SA, said by phone from New York . […]