The article analyses the implication of private sector representatives in the Millennium ecosystem assessment (MEA) (2001-2005). The article shows that, prior to this international biodiversity assessment, firms were involved in three coalitions: the greenhouse gas pro-trading coalition, the voluntary private standard coalition and the payment for environmental services coalition. These three coalitions all advocated a particular style of regulation that awarded an overwhelming place to market-based policy instruments. Corporate experts from the three coalitions identified were recruited to participate in the MEA. Thanks to the political visibility given to the ecosystem services concept by the MEA, private industry had an occasion to strengthen and legitimize their actions in favour of market-based environmental governance. At the same time, associating private sector representatives with the Millennium ecosystem Assessment process made it easier to disseminate the concept of ecosystem services.