Mercury Systems is trading 35.94% up at $115.93 after-hours, versus the regular-session close of $85.28, with available evidence pointing to broader risk-on sentiment following the Federal Reserve decision.
- No confirmed company-specific announcement explaining the September 18, 2026 surge was identified.
- The Nasdaq Composite was up 1.09%, though the unusually large after-hours move remains disproportionate to the market backdrop.