QuantumSi is trading 8.06% down at $1.43 on October 5, 2026, with no clear company-specific announcement or fresh catalyst identified.
- Its latest prominent news was interim Proteus platform data announced September 28, not a new October 5 event.
- The decline follows sharp gains of 33.64% on October 1 and 8.39% on October 2.
- Provided market-index moves were mixed and modest; available evidence does not establish a specific cause for the pullback.