rewrite this title Nvidia’s CEO sought to help the quantum companies and ended up causing another sell-off in the stocks

Nvidia CEO Jensen Huang spoke at the chipmaker’s annual conference on Thursday, aiming to walk back past comments on the decadeslong timeline needed for useful quantum computers.

But his latest foray into the quantum world appeared to have the opposite effect. Despite Huang’s public change of tune, several key stocks in the sector tumbled on Thursday, with D-Wave tanking 18% and the Quantum Defiance ETF (QTUM) dropping 2%.

At Nvidia’s first-ever “Quantum Day” event on Thursday, Huang said his January statements on quantum needing at least 15 years to become useful technology did not land as he intended. Huang also said he was surprised to see his commentary move public markets as it did in January.

“This is the first event in history where a company CEO invites all of the guests to explain why he was wrong,” Huang said Thursday.

In a show of support for the industry, Huang was joined by executives from several major quantum firms for a session, which is part of the megacap tech titan’s annual gathering called GTC happening this week. Nvidia’s announcement that it was hosting this “Quantum Day” had originally helped spark a recovery rally for the sector in January.

Huang said in January that 15 years was “on the early side” when laying out when to expect quantum computing technology would be deemed useful, prompting a sell-off in the sector. An expectation of 20 years is considered more reasonable, the CEO had said.

While Huang was aiming to soothe investors rattled by those prior comments, Thursday’s event did not appear to help the case for quantum stocks.

Even companies that accepted invitations to have executives join Huang on stage saw their shares fall. In addition to D-Wave’s plunge, Rigetti Computing and IonQ each dropped more than 9% on Thursday.

Needham analyst Quinn Bolton told clients that Huang’s insinuation about quantum’s branding was “one of the most contested portions” of the event. Tied to this, Bolton said, was the CEO’s belief that quantum computing should be marketed as a special tool that works alongside classical systems as opposed to a replacement.

“Jensen raised the idea that quantum computing might be poorly positioned, as calling a quantum system a computer sets unrealistic expectations,” Bolton said.

Nvidia has benefited from the rise of quantum, as research on this type of computer is done through simulators on powerful devices like what the company sells. The company is working on making technology to integrate graphics processing units, known in short as GPUs, with chips for quantum computing.

This week, Nvidia announced that it would build a research center in Boston where quantum companies can work with researchers at Harvard and the Massachusetts Institute of Technology.

Huang offered positive statements around the possible effect of quantum if it can be fully realized. But investors still appear skeptical on the sector, with the Quantum Defiance ETF down more than 4% this year.

“Of course, quantum computing has the potential and all of our hopes that it will deliver extraordinary impact,” Huang said during Thursday’s event. “But the technology is insanely complicated.”

— CNBC’s Kif Leswing contributed to this report.