D-Wave Quantum Inc. (QBTS) shares plummeted 11.94% in after-hours trading on Tuesday, after Nvidia CEO Jensen Huang cast doubts on the near-term prospects for viable quantum computing technology.

In a conference call, Huang stated that truly useful quantum computers are likely 15 to 30 years away, commenting: "If you said 15 years for very useful quantum computers, that would probably be on the early side. If you said 30 is probably on the late side, but if you picked 20, I think a whole bunch of us would believe it."

Huang's pessimistic outlook sparked a sell-off in quantum computing stocks. Besides D-Wave, Rigetti Computing dropped 10.3%, IonQ Inc fell 8.5%, and Quantum Computing Inc declined 6.8%. The Defiance Quantum ETF, which tracks the sector, slid 2.4%.