According to Windpower Intelligence, Vestas won 409MW during May, a fall of over 84MW on the previous month but enough to take it to number one. Siemens was in second place with 386MW.
Last month, GE held the top spot with 604MW, a result of a large number of installations in the US that followed on from the expiry of the production tax credit. As a sign of GE's possible reliance on the US market, the company's orders for May had fallen to 108MW.
Although project milestones continued to be hit, there are signs turbine manufacturers are struggling to bring in sales. Compared to May 2012, turbine orders are down 42%.
Latin America was the one exception to this. The number of newly signed turbine contracts for Latin America has almost doubled compared to the previous year. Brazil, Argentina, Costa Rica and Uruguay all handed out big orders with Vestas, Impsa and Siemens among the winners.
Speaking about the strong May performance from Vestas and Siemens, Windpower Intelligence and Data editor Eric Prideaux said: "It's clear from the data that geographic diversification is paying off for top manufacturers. These two firms are adept at offsetting risk in one market by pursuing opportunities in others."