• Israel prepares to invade the Gaza Strip.
• Exxon Mobil agrees to buy Pioneer for nearly $60 billion in stock.
• Birkenstock shares are set to begin trading.

Here are the most important news items that investors need to start their trading day:

1. Yielding a little

Stock markets rallied again – make that three days in a row – even as global concerns grew over the escalating war between Israel and militant group Hamas (more on that below). Bonds didn't trade Monday due to the holiday, so Tuesday was the first taste markets had of how yields would react to the latest geopolitical strife – and they fell, helping to give equities a lift. Earnings season is getting under way, as well. Pepsico helped things Tuesday, finishing the day up nearly 2% as the snack and soda producer boosted its profit outlook. On Wednesday, investors will chew over the latest whole sale inflation data as the producer price index for September hits. The Federal Reserve will also release the minutes from its latest policy-setting meeting. Follow live market updates.

2. Preparing to invade

Israeli troops are gathering at the border with the Gaza Strip, a government official said, as the nation's military prepares for a potential invasion of the Palestinian territory. "And that is to make sure that Hamas, at the end of this war, won't have military capabilities by which they can threaten or kill Israeli civilians. That is our military aim," said an Israeli Defense Forces spokesman. Israel has called up 300,000 reservists as it responds to a shocking and brutal sneak attack by Hamas terrorists who killed slaughtered hundreds of civilians and took dozens hostage. Meanwhile, the U.S. is negotiating a possible humanitarian corridor with Egypt as Palestinian civilians fee the siege of Gaza. Follow live updates on the Israel-Hamas war.

3. Birken-stock

Birkenstock expects to price shares for its initial public offering at $46 after the bell Tuesday, setting the stage for the German footwear brand to start trading Wednesday on the New York Stock Exchange. (Ticker: BIRK) That would give it a valuation short of the $9.2 billion it originally sought. Birkenstock's move comes as IPO market is still in an uncertain spot after shares from recent offerings by grocery shopping app Instacart, Johnson & Johnson spinoff Kenvue and makeup and wellness company Oddity Tech muddle along. Well, if the sandal fits ...

4. Exxon Mobil agrees to buy Pioneer

Oil giant Exxon Mobil said it had sealed a deal to buy Pioneer Natural Resources in an all-stock deal worth nearly $60 billion. It's Exxon's biggest purchase since its $81 billion deal for Mobil in 1998. The blockbuster agreement will give Exxon a stronger grip on fossil fuel production in the U.S. as Pioneer operates on a significant chunk of the Permian Basin, a sprawling oilfield located mainly in western Texas. Pioneer is the largest producer on the Permian.

5. A time for choosing

Who will succeed Rep. Kevin McCarthy, R-Calif., as speaker of the House, after he became the first person in American history to be booted from the office? It's not even clear to Republicans, who will vote on the matter Wednesday morning. Two firmly conservative candidates, Steve Scalise of Louisiana and Jim Jordan of Ohio, are vying for the position. Jordan, the chairman of the House Judiciary Committee, has former President Donald Trump's endorsement, while Scalise, the majority leader, has more leadership experience and a wide array of influential supporters in the House. The vote comes as the government weighs what to do next with Ukraine aid and the growing crisis in Israel and the Gaza Strip, as well as a new shutdown deadline next month. McCarthy, for his part, asked members not to re-nominate him for speaker.

– CNBC's Samantha Subin, Ruxandra Iordache, Gabrielle Fonrouge, Leslie Picker, Fred Imbert and Spencer Kimball contributed to this report.

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