We downgrade our recommendation for American Superconductor Corporation (AMSC) from Neutral to Underperform. Our downgrade is inspired by the refusal of its largest customer – Sinovel Wind Group Co. Ltd to accept further shipments. Sinovel is China’s largest and the world’s third largest wind turbine manufacturer. American Superconductor would be paying a high price for [...] (AMSC) American Superconductor Corporation Analyst Downgrades Shares to Underperform