The company has "gone into hibernation" and is "not operating anymore" Butterfield told Windpower Monthly. He said he is no longer employed by the firm, which is now running on a "skeleton staff".
However, Boulder is planning to retain its intellectual property, with a view to reactivating the company if it is able to enlist a manufacturer to install one of its generators.
When contacted by Windpower Monthly, Boulder CFO Chip Corboy said the company is "reducing its operational activities", and added "we are continuing dialogue with several interested parties and hope to conclude an agreement shortly".
He refused to be drawn on whether staff have been laid off or whether facilities have been closed down.
Boulder was set up in 2011 by Butterfield, the former chief engineer of the National Wind Technology Centre at the National Renewable Energy Laboratory.
Soon after, the company clinched $8 million in venture capital financing to help develop its direct-drive generator. The design is radically different and relies on a printed circuit board stator and sits outside the turbine's nacelle.
But the company took a bold step in March this year, releasing an array of new products, including a geared generator. At the time, CEO Andy Cukurs said one reason for this diversification was the lack of appetite within the wind industry for designs that break with convention, and a failure to find an industrial partner for its original design.
Cukurs current status at the company is unclear. While Corboy said he is still with the company, a Boulder staff member told Windpower Monthly he was no longer with the firm.