After Nvidia ( NASDAQ:NVDA ) CEO Jensen Huang said that "very useful" quantum computers are probably 15 to 30 years away, quantum computing stocks slumped drastically Wednesday. Arqit Quantum ( NASDAQ:ARQQ ) and D-Wave Quantum ( NYSE:QBTS ) dropped about 30% each; Rigetti Computing ( NASDAQ:RGTI ) shares fell 35%.

IonQ (IONQ) fell 28%; Quantum Computing ( NASDAQ:QUBT ), which said on Tuesday a $100 million stock offering, fell 32%. Commenting at a question-and-answer session at Nvidia's Consumer Electronics Show Financial Analyst event, Huang cited that for very practical quantum computers, a 15-year target would probably be seen as ambitious, he said.

While a 20-year schedule would undoubtedly have general acceptance, a 30-year projection would most certainly be considered as too late. With Quantum Computing ( NASDAQ:QUBT ) roaring 1,880%, Rigetti soaring 1,500%, and D-Wave Quantum up 985%, the losses follow significant increases in quantum computing companies over the past year. As of January 7, IonQ scored 290% and Arqit Quantum climbed 230%.

This article first appeared on GuruFocus .