A federal jury on Wednesday found Chinese turbine manufacturer Sinovel Wind Group guilty on US charges that it stole trade secrets from its former technology supplier AMSC, resulting in a loss of more than $800m for the Massachusetts-based company.

After an 11-day trial, Sinovel, which was AMSC’s largest customer until 2011, was found guilty by the jury in Madison, Wisconsin, on all charges that included conspiracy and wire fraud.