• Wall Street had a volatile day.
• McDonald's is continuing its $5 meal deal in most markets.
• Norfolk Southern's CEO was fired for cause.

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

1. Seesawing

Wednesday was a volatile day on the markets, as investors tried to figure out what the latest U.S. inflation data means for Federal Reserve policy. The S&P 500 gained 1.07% for the day. That's the first time since October 2022 that the broad market index has dropped 1% on an intraday basis only to close the day higher by more than 1%. The 30-stock Dow lost as much as 743.89 points through the day, but ended up adding 124.75 points, or 0.31%. The Nasdaq Composite, meanwhile, also wiped out its earlier losses and gained 2.17%. The swings came as the overall consumer price index hit its lowest annualized level since February 2021, but the core reading — which excludes volatile food and energy categories — rose slightly more than expected. But the markets picked up as Investors scooped up shares of mega-cap tech and semiconductor names in afternoon trading. Follow live market updates.

2. Meal deal

The $5 value meal is sticking around. McDonald's will extend its meal deal offer in most U.S. markets into December. Franchisees have been voting to decide if they want to keep the promotion, and roughly 80% of local markets opted in to the extension, the company said Thursday. The $5 deal started in June and was initially set to run only about four weeks, but it has been a hit as value became a key focus for the restaurant sector.

3. Norfolk Southern CEO ousted

Norfolk Southern CEO Alan Shaw was fired for cause after the company's board determined he engaged in a consensual relationship with legal chief Nabanita Nag, the company said Wednesday. Nag will also be terminated, according to the company. Shaw will be replaced by finance chief Mark George, who has been in his current role for nearly five years. Shaw had been CEO since 2022 and oversaw the railroad during the toxic East Palestine derailment. CNBC first reported on the board probe Sunday.

4. Modernizing

Moderna is looking for a new way forward after the rapid decline of its Covid business. The drugmaker said Thursday it would cut roughly $1.1 billion in expenses by 2027 as it tamps down on its research and development spending, pauses work on some products in its pipeline and scraps others. It also said it would try to win approvals for 10 new products through 2027. Also on Thursday, Moderna said it received positive late-stage trial results on its vaccine against respiratory syncytial virus, or RSV.

5. Meeting of the motors

General Motors and Hyundai Motor have agreed to explore "future collaboration across key strategic areas," the companies said Thursday. It's a move that aims to reduce capital spending and make the companies more efficient. In the non-binding memorandum of understanding, the automakers said they were potentially interested in collaborating to produce passenger and commercial vehicles, internal combustion engines and electric and hydrogen technologies. It's the first time Hyundai has entered into such an agreement, but GM has a long history of partnerships or deals, which have had varying levels of success.

— CNBC's Pia Singh, Kate Rogers, Rohan Goswami, Annika Kim Constantino and Michael Wayland contributed to this report.