Three of OPEC’s biggest oil producers raised monthly pricing for shipments to Asia, their largest regional buyer, after markets tightened on Saudi Arabia’s plan to slash output. Iraq, Abu Dhabi and Kuwait all raised pricing for February sales to Asia, taking their cue from the Saudis, who announced a similar increase last week. Iraq is the largest producer in the the Organization of Petroleum Exporting Countries after Saudi Arabia. The United Arab Emirates, in which Abu Dhabi holds most of the oil, and Kuwait rank third and fourth within the cartel, respectively.