ON Semiconductor is trading 6.02% up at $84.90, with chip-sector optimism linked to Micron’s strong results and AI-memory outlook providing the clearest reported context for the move. - ON Semiconductor closed October 1, 2026, at $80.08. - The provided price context shows a 4.18% regular-session gain before the additional after-hours rise; no new ON Semiconductor-specific announcement was identified.