Investing in quantum

The selloff

Quantum computing stocks had a bruising week in July 2026, and the figures show how sharp the reversal has been. IonQ traded around $34.25, down 20.4 per cent on the week and 59.5 per cent from its high. Rigetti sat at roughly $13.92, off 16.2 per cent on the week and 76.1 per cent from its peak. D-Wave was near $16.59, down 17.6 per cent and 64.5 per cent from its high, while Quantinuum held up comparatively better at about $56.49, still down 19.8 per cent on the week and 34.9 per cent from its top. None of this happened in isolation: the Philadelphia Semiconductor index had fallen more than 11 per cent from its June peak into bear-market territory, which amplified every move in the more speculative quantum computing stocks.

Bull and bear

The sell-off has brought the two competing narratives about the sector into sharp relief. The bear case, argued forcefully by Bank of America, is straightforward: there are as yet no commercially relevant quantum algorithms, no fault-tolerant hardware in existence, and any real monetisation is still measured in years rather than quarters. On that reading, today’s quantum computing stocks are priced for a future that has not been proven and may arrive slowly. The bull case does not dispute the technical immaturity. It rests instead on demand that is largely indifferent to it: governments are buying regardless of near-term commercial returns, and the migration deadlines written into law give at least part of the sector a floor of guaranteed spending. That legally binding demand is what distinguishes quantum from a purely speculative technology wager: even if the science disappoints commercially for several more years, the migration mandates and public purchases keep money flowing to the firms positioned to serve them.

Milestones to watch

Because valuations are running so far ahead of revenue, the sensible way to follow quantum computing stocks is through concrete technical milestones rather than price alone. Several are worth marking on the calendar. IBM has said it intends to make a verified quantum-advantage claim by the end of 2026, which, if independently confirmed, would be a genuine marker. Quantinuum’s Sol machine is expected at 192 qubits, and QuEra is targeting 100 logical qubits, a figure that speaks to error-corrected rather than raw performance. Microsoft and Atom Computing have pointed to a 50-logical-qubit machine named Magne in 2027, and PsiQuantum is working to integrate its Brisbane and Chicago sites. Further out, IBM has set 2029 for Starling, its planned large fault-tolerant system.

Raw versus logical qubits

What ties the watch list together is the distinction between raw qubit counts and logical, error-corrected qubits, which is where the real difficulty lies. A jump to more physical qubits makes for an easy headline; a demonstration of a handful of reliable logical qubits, of the sort implied by the QuEra and Magne targets, is the harder and more meaningful achievement. Investors who follow only the largest number quoted will regularly be misled, because the quantum computing stocks that eventually reward patience are likely to be the ones that clear the error-correction bar rather than the qubit-count one.

The bottom line

The honest summary is that this is a sector where the science and the share prices are moving on very different clocks. The technology is advancing in steady, verifiable steps, while the stocks swing violently with sentiment and with the wider semiconductor market. That gap is the source of both the opportunity and the danger. For readers weighing it up, the disciplined approach is to watch the milestones above, treat any single week’s move with suspicion, and remember that this page is information and not investment advice. For the underlying technology, see our quantum explainers and the main quantum hub.