OPEC+, a coalition of some of the world’s top oil producers, surprised markets over the weekend with plans to boost production by more than half a million barrels a day. The increase comes at a time when investors are worried about oversupply.

So what was behind the decision? Bloomberg’s Joumanna Bercetche breaks it all down with Big Take host David Gura from Vienna, where members of the oil cartel and executives from around the world are gathered for the Ninth OPEC International Seminar.