Quantinuum shares rose 13% in their Nasdaq debut after the company raised $1.68 billion in an upsized IPO, marking a stronger first-day performance than previously indicated and highlighting investor appetite for quantum computing listings. The company, formed through the merger of Honeywell's quantum computing business and Cambridge Quantum, trades under the ticker QNT. The debut adds to signs that public-market investors are willing to back companies tied to emerging computing technologies as the sector pushes to prove commercial viability.