Arqit Quantum is trading at $16.23, up 5.98%, with the Nasdaq Composite’s 0.66% gain offering broader technology-market context.
- No new company-specific announcement on October 21, 2026, was found to explain the move.
- Arqit announced an October 20 strategic investment in Sirius Computer to advance quantum-safe communications for defence and government; available coverage does not establish it as the direct cause of the October 21 move.
- The stock is in live trading; reliable volume information was not available.