5 things to know before the stock market opens Wednesday

• McDonald's shares tanked after an E. coli outbreak at the chain killed 1 person and hospitalized 10 others.
• The IRS raised federal income and capital gains tax bracket thresholds, while also boosting estate and gift tax exemptions.
• Coca-Cola announced third-quarter earnings that beat Wall Street expectations.

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

1. A rough patch

Stock futures slid Wednesday after the S&P 500 posted its first back-to-back loss since early September. Futures tied to the S&P 500 dropped 0.1%, while Dow futures lost 0.4% and Nasdaq 100 futures fell 0.2%. The yield on the benchmark 10-year Treasury note rose 3 basis points to 4.23%, putting pressure on both the S&P 500 and Dow, which dropped 0.05% and 0.02%, respectively, on Tuesday. The Nasdaq Composite rose close to 0.2%. Follow live market updates.

2. Boeing's big day

Boeing and new CEO Kelly Ortberg are set for a big day as the company announced earnings Wednesday morning. The aircraft manufacturer reported an adjusted loss per share of $10.44, while analysts surveyed by LSEG had expected a loss of $10.52, and revenue came in at $17.84 billion versus $17.82 billion. Ortberg will lead a call with analysts for the first time since taking the helm of the aviation giant in August that has been at the center of widespread safety issues and a massive strike. More than 32,000 machinists on strike will vote on a new contract proposal, with results expected to come Wednesday night. Analysts are cautiously optimistic that the proposal, which requires a simple majority of the vote, could pass, putting an end to the more than five-week work stoppage that has halted most of the company's production of airplanes.

3. McDonald's E. coli outbreak

McDonald's shares sank in extended trading Tuesday after the Centers for Disease Control and Prevention said an E. coli outbreak was tied to the chain's Quarter Pounder burgers. The agency said 49 cases had been reported in 10 states between Sept. 27 and Oct. 11, with most of the illnesses in Colorado and Nebraska. An older adult in Colorado died while 10 others were hospitalized. Initial findings from the ongoing investigation show that some of the illnesses may be linked to slivered onions that are used in the Quarter Pounder and sourced by a single supplier that serves three distribution centers, according to a statement from McDonald's. The company said it has paused distribution of slivered onions in the affected area and has made the Quarter Pounder temporarily unavailable in several Western states.

4. IRS adjusts provisions

The IRS announced Tuesday a slew of updated tax provisions for 2025. The IRS raised the income thresholds for each federal income tax bracket, which applies to tax year 2025 for returns filed in 2026. The top rate of 37% applies to individuals with taxable income above $626,350 and married couples filing jointly earning $751,600 or more. Capital gains tax brackets were also boosted, which apply to assets owned for more than one year. Meanwhile, the standard deduction will rise to $15,000 for single filers and $30,000 for married couples filing jointly starting in 2025. Estate and gift tax exemptions, tax-free transfers during life and at death, were also hiked to $13.99 million per person in 2025, up from $13.61 million in 2024.

5. Coca-Cola

Coca-Cola announced third-quarter earnings on Wednesday that beat Wall Street expectations as higher prices helped offset slow demand for beverages. The company reported adjusted earnings of 77 cents per share compared with 74 cents per share estimated by an LSEG survey of analysts. Revenue was $11.95 billion which topped the $11.60 billion analysts predicted.

— CNBC's Pia Singh, Leslie Josephs, Annika Kim Constantino, Jacob Pramuk, Kate Dore and Amelia Lucas contributed to this report.