Rigetti Computing, IonQ, and other quantum stocks fell more than 40% after Nvidia CEO Jensen Huang told Wall Street analysts that “very useful quantum computers” are likely 20 years away.

Quantum computing stocks sank on Wednesday, pausing a year-long rally, after Nvidia CEO Jensen Huang said the technology's practical use was likely two decades away. The long wait outlined by Huang for "very useful quantum computers" throws cold water on a sector that was already expected to spend millions more on the technology,