Top Wall Street analysts changed their outlook on these top names. For a complete view of all analyst rating changes, including upgrades and downgrades, please see our analyst ratings page. Morgan Stanley analyst Joseph Moore initiated coverage on Allegro MicroSystems, Inc. (NASDAQ:ALGM) with an Equal-Weight rating and announced a price target of $21. Allegro Microsystems shares closed at $22.01 on Wednesday. See how other analysts view this stock.UBS analyst Steven Fisher initiated coverage on Vulcan Materials Company (NYSE:VMC) with a Buy rating and announced a price target of $349. Vulcan M…