And with Microsoft shares up by 9% and Meta gaining 11% before the open, the S&P 500 would have a hard time being anything but up today. In fact, that index is gaining nearly 1% in premarket futures trading. The Nasdaq, of which both Microsoft and Meta are also members, is up more than 1%.

Wall Street's AI heavyweights added a combined half a trillion dollars in stock market value late on Wednesday after quarterly reports from Microsoft and Meta Platforms showed massive investments in the emerging technology were paying off.