Stocks making the biggest moves before the bell: Nasdaq, Illumina, Oracle, Carnival and more
Check out the companies making headlines in premarket trading.

Nasdaq — The exchange operator's shares dropped 7.7% following the announcement of its deal to buy Adenza, the software firm owned by Thoma Bravo. The deal, valued at about $10.5 billion, would be Nasdaq's largest acquisition as the company sharpens its focus on financial technology and attempts to diversify.

Illumina — The biotech stock rose 2% in premarket trading after Illumina announced a CEO transition plan Sunday. CEO Francis deSouza resigned, effective immediately, but will stay on as an advisor through July 31. The move follows pressure from activist investor Carl Icahn.

Nio — Shares popped more than 4% after the Chinese electric car maker said it was cutting prices for its vehicles and ending free battery swaps for new buyers. Last week, Nio also said it was delaying its capital expenditure projects. Nomura assumed coverage of Nio with a neutral rating Sunday, after previously rating it a buy.

SentinelOne — Shares rose 5.2% following an upgrade to overweight from equal weight by Morgan Stanley, which said the market hasn't correctly priced the stock's inherent asset value. The cybersecurity stock was hit with a salvo of downgrades after it reported weaker-than-expected first-quarter revenue and disappointing current-quarter and full-year guidance on the metric earlier in June.

Bill.com — Shares shed 4.8% in the premarket after Morgan Stanley downgraded the expense management platform to equal weight from overweight. The firm said Bill.com has limitations to expansion and could see increased competition.

Oracle — The IT stock added 4.7% in Monday's premarket as investors awaited earnings for the fiscal fourth quarter expected after the bell. Wolfe Research upgraded the stock to outperform from peer perform over the weekend, while Evercore ISI said Friday that it anticipated a strong quarterly report and positive commentary around the cloud business. Evercore ISI, Barclays and JPMorgan Chase all raised their respective price targets for the stock in recent days.

Carnival — The cruise stock popped 5.5% following an upgrade from JPMorgan. The Wall Street firm upgraded shares to overweight, citing continued demand momentum in the cruise industry.

— CNBC's Jesse Pound, Samantha Subin and Michelle Fox contributed reporting.