Stocks making the biggest moves premarket: Airbnb, Oracle, American Express and more

cnbc.com:

Check out the companies making headlines in premarket trading.

Zynex, Coherus BioSciences, Universal Insurance Holdings — Coherus, Zynex and Universal Insurance stock fell on news from S&P 500 Dow Jones indices that the stocks would be moving within smallcap indexes. Coherus is leaving the Midcap 400 for the midcap 600, while Universal Insurance is leaving the midcap 600 altogether. Zynex tumbled nearly 6% on news that the firm is leaving the small cap 600 index.

American Express — Stock in the credit card giant ticked up 0.5% following an upgrade to outperform from sector perform from RBC earlier on Tuesday.

Airbnb — Shares of the vacation rental company rose more than 4% on the heels of the S&P Dow Jones Indices announcement on Friday that Airbnb will join the S&P 500 later this month. The S&P 500 is widely tracked by large index funds, which could create buying pressure on Airbnb's stock in the weeks ahead.

NextGen Healthcare — The healthcare stock climbed more than 11% following a Bloomberg report Monday that the company was in late-stage talks with potential acquirer Thomas Bravo.

Oracle — The software stock added 1.5% in premarket trading following an upgrade to overweight from equal weight by Barclays. The firm said the company's cloud business should feel tailwinds from artificial intelligence.

Brady Corporation — Shares climbed nearly 11% after the company reported quarterly results. Brady posted an adjusted $1.04 profit per share, while analysts polled by FactSet forecast 93 cents.

Warner Bros. Discovery — Shares dipped 1.2% after the company warned that strikes from writers and actors could negatively impact cash flow by a range of $300 million to $500 million.

— CNBC's Alex Harring and Jesse Pound