Nvidia Corp., the poster child of the AI frenzy, sank 17 per cent and headed toward the biggest market-cap loss for a single stock in market history. The AI leader wiped of $500 billion of its market value and shed 21 per cent off its stock price in two days.

Wall Street is pointing slightly lower in early trading but is on track to close the week with solid gains on healthy quarterly earnings reports from large U.S. corporations.

Many quantum computing stocks have risen well above Wall Street's price targets, but this one still has room to climb.