What counts as a quantum computing stock?
There are two very different ways to invest in quantum computing, and mixing them up is the most common mistake retail investors make. Pure-play quantum companies — IonQ, Quantinuum, D-Wave, Rigetti, Infleqtion, Xanadu — earn (or plan to earn) essentially all of their revenue from quantum hardware, software or quantum-safe security. Their stock prices move almost entirely on quantum news, which makes them extremely volatile: most are pre-profit and trade on expectations for the late 2020s. We break down what their valuations actually tell you in IonQ, Rigetti and D-Wave: What Quantum Stocks Actually Tell You.
Big tech plays the same race with different stakes. IBM has spent over $15 billion on quantum R&D, Google's Willow chip set the error-correction benchmark, Microsoft bets on topological qubits, and Amazon sells quantum access through AWS Braket. For these companies quantum is a research arm, not the business — so their stocks barely react to quantum milestones. The full picture is in The Tech Giant Quantum Arms Race.
2026: the year quantum went public
Until recently most serious quantum companies were private. That changed fast: Infleqtion (INFQ), Xanadu (XNDU) and Horizon Quantum (HQ) all listed in early 2026; in June, Quantinuum — the Honeywell spin-out — completed the largest quantum IPO ever at a valuation near $16 billion; and in July, Finland's IQM (IQMX) became the first European quantum company on the Nasdaq. The US government simultaneously took equity stakes in nine quantum companies through $2 billion in CHIPS Act grants. The private names still worth watching (PsiQuantum, SandboxAQ) are covered in The Quantum Unicorns.
Quantum-resistant crypto — and quantum-exposed crypto
The crypto assets in this screener are quantum-first projects only: chains built from day one around post-quantum cryptography. Quantum Resistant Ledger (QRL) uses hash-based XMSS signatures that Shor's algorithm cannot break, QANplatform (QANX) is a quantum-resistant hybrid blockchain for enterprise applications, and Cellframe and Mochimo take their own post-quantum approaches. Bitcoin and Ethereum are deliberately not listed here — they are not quantum companies, they are quantum targets: both still rely on elliptic-curve signatures that a large quantum computer could forge, and neither has completed a post-quantum migration. That story gets its own analysis in Bitcoin's Quantum Threat and Ethereum's Post-Quantum Migration.
Why this list exists
This site tracks the countdown to Q-Day — the moment a quantum computer breaks RSA encryption. The companies on this page are the ones building toward that moment, defending against it, or both. Whether Q-Day lands in 2029 or 2035, the capital is flowing now.