After the most popular quantum-computing stocks tumbled last week, they're sinking again today.

Rigetti (RGTI) is dropping 23%, while IonQ (IONQ) is giving back 10% and D-Wave Quantum (QBTS), which disclosed today that it may sell more shares of its stock, is plunging nearly 30%.

A modern computer datacenter, running an advanced quantum computer system.

The sector is dropping sharply again after Meta (META) CEO Mark Zuckerberg suggested that quantum computing would not be "practical" for a long time.

Last week Nvidia (NVDA) CEO Jensen Huang made similar comments, sparking the huge downturn by quantum names.

Zuckerberg's Statement and the Quantum Sector's Defense

"I'm not really an expert on quantum computing, but my understanding is that it's still quite a ways off from being a truly practical paradigm," Zuckerberg was quoted as telling Joe Rogan on the latter man's podcast.

After Huang suggested last week that quantum technology would not be "very useful" for about 20 years, a number of CEOs in the quantum sector refuted his thesis. For example, D-Wave CEO Alan Baratz said that the company's annealing quantum computing is "supporting businesses today... to solve their hard problems."

Separately, D-Wave today disclosed in a regulatory filing that it could sell as much as $150 million of QBTS stock.

The latter news, along with the weakness of small-cap growth stocks today, is likely to be putting pressure on quantum names today.

While we acknowledge the potential of QBTS, our conviction lies in the belief that some AI stocks hold greater promise for delivering higher returns, and doing so within a shorter time frame. If you are looking for an AI stock that is more promising than QBTS but that trades at less than 5 times its earnings, check out our report about the cheapest AI stock.

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Disclosure: None. This article is originally published at Insider Monkey.