• All three major averages wrapped up a solid month, but there were some hiccups at the end.
• Nvidia and AMD unveiled their next generation of AI chips.
• GameStop shares rallied yet again after a post from Roaring Kitty, the trader who inspired 2021's epic short squeeze.

Here are five key things investors need to know to start the trading day:

1. Yay for May

May ended up being a strong month for stocks, as the three major averages all posted their sixth positive month in seven. The Nasdaq Composite shined the most, marking its best month since November with a gain of 6.9%. The S&P 500 rose 4.8% while the Dow Jones Industrial Average added 2.3% in May. The end of the month brought some turbulence, though. Even with the Dow adding more than 500 points on Friday, the three averages ended the month more than 1% off their record highs. Looking to June, the first week will bring economic updates including manufacturing data on Monday and a key jobs report on Friday. Follow live market updates.

2. And another one

The artificial intelligence chip market is in a frenzy. AI darling Nvidia unveiled its next generation of AI chips, called "Rubin," on Sunday, just months after the March announcement of its upcoming "Blackwell" model. Those Blackwell chips are still in production and are expected to ship to customers later this year. CEO Jensen Huang has pledged to release new AI chip technology on a one-year basis, even faster than the company's previous two-year timeline. AMD followed suit on Monday, announcing its own new artificial intelligence chips as it seeks to compete with Nvidia and Intel. AMD is releasing chips for next-generation AI laptops and another line for desktops.

3. Change of plans

The Organization of the Petroleum Exporting Countries and its allies — the influential oil alliance known as OPEC+ — has extended its collective crude production cuts into 2025. The cuts were set to expire this year, and analysts and OPEC+ delegates were anticipating the decision to change the timeline. The coalition will produce a combined 39.725 million barrels per day next year, it said. A subset of the OPEC+ alliance, including major players Saudi Arabia and Russia, also changed the timeline of two other sets of supply curbs, stretching them over different periods than initially planned. Oil prices slipped early Monday despite the move.

4. GameStop roars

GameStop shares saw a huge rally, yet again, on speculation that Keith Gill, the man behind the "Roaring Kitty" account that inspired 2021's epic short squeeze, could have a huge position in the video game retailer. The stock was up more than 70% in premarket trading Monday. Gill, who also goes by DeepF------Value on Reddit, had posted a screenshot of what could be his portfolio holding a significant amount of GameStop common shares and call options. The post was not verified by CNBC and he didn't post on the WallStreetBets forum where he had previously made infamous trade updates.

5. Trains and automobiles

Ford is looking to the future. But its idea of what's next looks a little different than some other companies, which are looking to downsize as employees have grown accustomed to working from home. Meanwhile, Fordhas spent nearly $1 billion restoring and reopening an abandoned, century-old train station and other buildings to create the automaker's new technology campus. Ford Chair Bill Ford Jr., a great-grandson of company founder Henry Ford and leader of the project, said the 30-acre campus will be key for talent acquisition and retention. The company plans to house at least 2,500 employees in the building along with other occupants. So far, about two-thirds of the tower has scheduled tenants or planned use cases, officials said.

— CNBC's Jesse Pound, Rebecca Picciotto, Kif Leswing, Ruxandra Iordache, Yun Li and Michael Wayland contributed to this report.

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