 BlackRock Inc. boosted its stake in shares of American Superconductor Co. NASDAQ:AMSC by 1.8 in the 1st quarter, according to the company in its most recent disclosure with the SEC. The firm owned 1,437,464 shares of the technology companys stock after buying an additional 25,403 shares during the quarter. BlackRock Inc. owned approximately 6.37 of ... 