Allegro Microsystems is trading 4.61% up at $36.75 on September 25, 2026; no clear company-specific announcement explaining the move surfaced in the available search results, and broader-market gains may be a contributor. - Major U.S. indexes are up more than 0.5%, providing context rather than a confirmed direct cause. - The investor-relations page lists July 30 as the latest results announcement; available results do not establish unusual trading volume.