Copa Holdings is trading 18.42% down at $110.38 after closing at $135.31 on September 22, 2026, with no reliable company-specific announcement, earnings release, or late-breaking catalyst identified for the after-hours decline. - Its latest available update, August traffic data, showed 16.8% year-over-year growth and an unchanged 88.3% load factor; the report does not clearly explain the drop. - Markets were mixed: the Nasdaq rose 0.61%, while the S&P 500 and Dow declined modestly, so broader direction does not clearly account for the move.