Polaris Capital Management LLC owned 0.07% of Amphastar Pharmaceuticals worth $806,000 at the end of the most recent reporting period. GAMMA Investing LLC lifted its holdings in shares of Amphastar Pharmaceuticals by 4,151.3% in the 1st quarter. Finally, Exchange Traded Concepts LLC purchased a new position in Amphastar Pharmaceuticals in the 1st quarter valued at approximately $257,000. Amphastar Pharmaceuticals Price PerformanceAmphastar Pharmaceuticals stock opened at $26.75 on Friday. Featured ArticlesReceive News & Ratings for Amphastar Pharmaceuticals Daily - Enter your email address below to receive a concise daily summary of the latest news and analysts' ratings for Amphastar Pharmaceuticals and related companies with MarketBeat.com's FREE daily email newsletter.