The Danish firm has 36% of signed turbine purchase agreements for projects that have announced turbine suppliers and are under construction in the US. GE has 39% and Siemens 15%.
The figures were announced as part of the third quarter report from the American Wind Energy Association (AWEA).
Of the completed projects that came online in the first three quarters of 2015, GE had 53%, Vestas 30% and Siemens 6%.
More than 13.25GW of wind capacity is under construction in the US, and an additional 4.1GW is in an advanced stage of development.
More than 800MW wind-power deals with non-utility corporations should be signed in the US within the next quarter, said Charles Esdaile, a managing partner at Altenex, which facilitates such deals.
"As Fortune 500 firms see others putting their money where their mouth is… there is a snowballing of new deals," he told the AWEA-hosted webinar.
This week, consumer goods firm Procter & Gamble said it would buy 80% of the output from a 123MW EDF Renewable Energy project under development in Texas.
American cities are also joining the ranks of non-utility purchasers of wind power in the US, driven by their environmental and fiscal goals, said AWEA.
Iberdrola Renewables signed a 20-year power purchase agreement with the District of Columbia during the third quarter for the output of the company’s 46MW South Chesnut 2 project in Pennsylvania, which is expected to save taxpayers $45 million over the life of the contract and help the nation’s capital meet its goal of 50% renewables by 2032.
New York issued a request for information for renewable energy supply during the same quarter, while the City of Aspen reached its goal of running on 100 per cent renewable energy. It buys power from wind farms in Nebraska and South Dakota.
"I think you are going to continue to see this trend advance," says Kevin Helmich, managing director of Midwest and eastern origination for Iberdrola.