Every publicly traded quantum computing company is a hardware company. IonQ traps ions. Rigetti builds superconducting chips. D-Wave makes annealers. Xanadu, which is completing its own SPAC next week, builds photonic processors. Even Quantinuum, which went public via traditional IPO, makes trapped-ion machines.
Horizon Quantum just broke the pattern.
On March 20, Horizon Quantum Computing completed its SPAC merger with dMY Squared Technology Group and began trading on Nasdaq under the ticker “HQ,” with warrants under “HQWWW.” The deal raised approximately $120 million in gross proceeds before transaction expenses. Shareholders approved the combination on March 17.
Horizon does not build quantum computers. It builds the software that runs on them. All of them.
But the software angle isn’t the most interesting part of this story. The SPAC sponsor is.
Harry You’s Quantum Franchise
Harry You, chairman and CEO of dMY Squared, is not new to quantum IPOs. He’s the reason IonQ exists as a public company. Back in 2021, You and dMY Technology Group took IonQ public in what became the first quantum computing IPO. Period. That deal put quantum on the Nasdaq map.
Now the same operator, through a different dMY vehicle, just took the first quantum software company public. One person is becoming the gatekeeper for quantum’s route to public markets. That concentration is worth paying attention to.
And it’s not just dMY. Look at the full list. IonQ went public via SPAC (dMY, 2021). Rigetti merged with Supernova Partners in 2022. D-Wave merged with DPCM Capital in 2022. Xanadu’s SPAC with Crane Harbor is expected to close March 26, targeting $302 million. That’s five out of six public quantum companies using SPACs. Quantinuum’s traditional IPO is the only exception.
Five out of six. That’s not a coincidence. That’s a tell.
Traditional IPOs require convincing institutional investors your company has near-term revenue potential. SPACs let you go public on a thesis. They are the financing vehicle for companies that cannot yet prove product-market fit but need capital to keep building. That is not a criticism. It is a description of where quantum computing actually is as an industry in 2026: a collection of thesis-stage bets, bankrolled by sponsors who specialize in getting pre-revenue companies onto exchanges.
The Windows Bet
Founded in 2018 by Dr. Joe Fitzsimons, an Irish quantum physicist with over 20 years in the field, Horizon is a hardware-agnostic quantum software infrastructure company. Its core product is Triple Alpha, an integrated development environment that lets developers write quantum applications that run across different quantum computing platforms regardless of the underlying hardware.
That is a specific and deliberate strategic choice. Quantum computing has a fragmentation problem. Superconducting qubits work differently from trapped ions, which work differently from photonic systems, which work differently from neutral atoms. Writing code for one platform does not mean it runs on another. If you are a bank or a pharmaceutical company trying to evaluate quantum computing, you either pick a hardware vendor and lock in, or you wait.
Horizon is betting that this fragmentation makes the software layer more valuable than any individual hardware play. The logic is borrowed directly from the PC era. In the 1980s, dozens of companies built personal computers. Most of them no longer exist. Microsoft built the operating system that ran across all of them. The value did not accrue to the company that built the best hardware. It accrued to the company that made the hardware interchangeable.
You himself seems aware of this parallel. “The ones who are most successful in building long-term shareholder value have been those that build software infrastructure and operating systems,” he said in the press release.
So the guy who took IonQ (hardware) public in 2021 is now explicitly saying the software layer is where the long-term value lives. Read that however you want.
The Risk
The obvious vulnerability is timing. Hardware-agnostic software is only valuable when there is hardware worth abstracting across. Quantum computers in 2026 are still too error-prone and too small for most commercial applications. Horizon needs enough quantum hardware to mature, across enough modalities, for its cross-platform value proposition to matter. If one hardware approach wins decisively and early, the abstraction layer is unnecessary. If quantum utility keeps getting pushed further out, Horizon burns cash waiting for a market that isn’t there yet.
The $120 million is modest compared to Xanadu’s $302 million. But Horizon is a software company. Its capital requirements are structurally different from hardware shops that need fabrication facilities and cryogenic infrastructure. $120 million goes further when you are writing code than when you are cooling superconductors to near absolute zero.
Every major computing platform in history, from mainframes to PCs to cloud, eventually separated the hardware from the software and the value migrated up the stack. If quantum computing follows the same pattern, and there is no obvious reason it wouldn’t, Horizon is positioning itself to collect rent from every hardware vendor below it.
Whether it works depends on timing and on whether quantum stays fragmented long enough for the middleware to matter. History says the abstraction layer wins. But history also assumes the underlying technology actually reaches commercial viability. That part is still an open question, and every SPAC sponsor in quantum is betting their fund that the answer is yes.
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