Federal and enterprise teams calibrating post-quantum migration deadlines now have a government-vetted list of which quantum hardware approaches Washington considers plausible, rather than relying on unverified vendor claims.

On October 7, 2026, DARPA named four companies that advanced to Stage C, the final stage of its Quantum Benchmarking Initiative: Atom Computing (neutral-atom arrays), Diraq (silicon CMOS spin qubits), IBM (modular superconducting processors), and IonQ (trapped-ion). They join Microsoft and PsiQuantum, which reached Stage C through QBI’s precursor program, bringing the cohort to six across four distinct qubit modalities. DARPA says it has evaluated more than 20 companies since QBI launched in mid-2024.

Stage C has specific parameters. It verifies whether a performer’s proposed utility-scale system “can ultimately be constructed as designed and operated as intended,” testing hardware against the roadmaps submitted earlier. It is not a demonstration of a working cryptographically relevant quantum computer. QBI’s target is utility-scale operation, where computational value exceeds cost, by 2033, and DARPA states it does not yet know which team or approach will get there.

For PQC readiness, the practical takeaway is twofold. This is not evidence that harvest-now-decrypt-later risk has accelerated, so do not reset migration deadlines based on this announcement. It does confirm that CRQC timeline risk remains architecture-agnostic, which argues for diversifying migration planning rather than betting on one modality.

IonQ said its agreement carries a ceiling of $300 million through 2029, a figure sourced to IonQ alone. Trade-press contract specifics for Atom Computing and Diraq remain single-sourced and unverified.

Watch for further Stage C promotions, which DARPA expects soon, as the clearest public gauge of credible hardware progress.