Horizon Quantum, a Leading Quantum Software Infrastructure Company, Closes its Business Combination with dMY Squared
Horizon Quantum's $546M SPAC merger closes this week — and the quantum software story just got more interesting. The deal, combining Horizon Quantum Computing with dMY Squared Technology Group, won shareholder approval on March 17th.
image from GPT Image 1.5
The deal, combining Horizon Quantum Computing with dMY Squared Technology Group, won shareholder approval on March 17th. The company will list on the NYSE under the ticker HQ. But the numbers tell a narrower story than the company's framing suggests.
The PIPE financing — $111.9 million, oversubscribed from a $50 million target — is the most concrete signal of investor appetite. Notably, IonQ co-invested, alongside a Fortune 50 technology company. That's not nothing. IonQ placing capital alongside a software bet is a vote of confidence in the thesis that quantum software is where value accrues as the hardware matures.
But the most revealing detail in the filing isn't the balance sheet. It's Fitzsimons's framing of where quantum computing actually is.
"Quantum computing is starting to reach an inflection point," he told SPAC Insider in March. His specific argument: the last 18 months have brought the first demonstrations that error rates can be suppressed below the physical qubit error rate — meaning error correction can run faster than errors accumulate. "We're really getting to the point where the technology has gone through this step change." He cited August 2024 as the inflection point.
That is a significant claim. Error correction is the central engineering challenge in quantum computing — the thing that separates "interesting physics experiment" from "useful machine." If the field has genuinely crossed that threshold, the commercial timeline for quantum advantage accelerates. If it hasn't scaled yet, the inflection is real but years from product.
What makes Horizon unusual is the hardware bet. The company operates a fully integrated quantum testbed at its Singapore headquarters — a claim it makes explicitly: first quantum software company to own and operate its own quantum computer. That vertical integration is unconventional. IBM, Google, and IonQ build hardware. Most software companies rent time on cloud quantum systems via API. Owning the full stack gives Horizon control over the feedback loop between software and hardware, but it also means CapEx exposure that pure software models avoid.
The Alice & Bob partnership adds texture. The Paris-based company is building fault-tolerant quantum computers using cat qubits — a specific approach to suppressing errors that has attracted attention for its theoretical scalability. Integrating cat qubit emulators into Horizon's Triple Alpha platform positions the company to claim readiness for the error correction era before most competitors. Whether that claim holds up depends on what Alice & Bob actually delivers.
Horizon also launched Beryllium, its third programming language in the Triple Alpha platform family, alongside Helium and Hydrogen. The pitch is hardware-agnostic object-oriented quantum programming with pulse-level control — the kind of abstraction that would make quantum development accessible to classical software engineers. In practice, quantum hardware still requires deep specialist knowledge. Beryllium is a bet on where the tooling needs to be in three to five years.
The board appointments are worth noting: Harry You, chairman of dMY and Broadcom board member, brings the Oracle and Accenture CFO pedigree. Jill Turner, CHRO at Broadcom. A CFO from Grab. This is a public-market-ready governance team, not a lab.
What's the actual story here? Horizon is claiming that quantum software is reaching the point where error correction and hardware control are tractable engineering problems, not just research. The PIPE oversubscription validates that thesis in the market. The Alice & Bob partnership and the Singapore testbed are the operational bets that back it up.
The counter: $546M is not enormous for a quantum company with meaningful hardware exposure. IBM and Google are spending that annually on R&D. The "first quantum software company to own its own quantum computer" framing is clever positioning, but a testbed in Singapore is not the same as scalable infrastructure. The quantum programming language ecosystem is still nascent.
The deal closes this week. Horizon will list as HQ on the NYSE. Whether the error correction inflection is real — or just the kind of inflection that keeps quantum companies perpetually three years away — will become apparent in the results.
The SPAC Insider podcast transcript with CEO Joe Fitzsimons and chairman Harry You is here: https://www.stocktitan.net/sec-filings/DMYY/425-d-my-squared-technology-group-inc-business-combination-communicat-4f8986f70406.html
Horizon's March 10 investor milestones announcement is here: https://www.minichart.com.sg/2026/03/10/horizon-quantum-computing-achieves-key-milestones-secures-111-9m-pipe-financing-and-advances-quantum-software-ahead-of-dmy-merger-123/
