• President Joe Biden dropped out of the 2024 presidential race and endorsed Kamala Harris.
• Big Tech earnings start this week.
• Delta Air Lines battled lingering flight disruptions on Monday after Friday's global IT outage.

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

1. Trading places

The S&P 500 fell 1.97% last week, while the Nasdaq Composite lost 3.65%, marking their biggest weekly losses since April. The tech-heavy Nasdaq snapped a six-week winning streak with the losses. But it wasn't all bad news for the markets. The Dow Jones Industrial Average advanced 0.72%, while the small cap-focused Russell 2000 climbed 1.68%, as investors rotated out of this year's megacap winners in favor of smaller names. This week, traders will be watching earnings, central bank policy and the political landscape. Jay Hatfield, CEO at Infrastructure Capital Advisors, said he expects a "muted stock market reaction" to President Joe Biden dropping out of the presidential race, as it had been largely expected. Follow live market updates.

2. Biden drops out

President Joe Biden announced Sunday that he's leaving the 2024 presidential race, quitting his re-election bid against former President Donald Trump after weeks of pressure from his own party to drop out. He endorsed his vice president, Kamala Harris, as the Democratic Party's nominee. "While it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as President for the remainder of my term," Biden wrote in a post on social media, adding that he'll address the nation later this week. Harris, 59, saw a surge in fundraising money from big Democratic donors after the announcement, according to people familiar with the matter. Harris has several next steps to take before the general election: She has to select a running mate, secure a majority of delegates and win over the support of Biden's allies and undecided voters. Follow live updates.

3. Tech time

It's time for Big Tech earnings. Google-parent Alphabet and Tesla are set to report this week, along with more than 100 other S&P 500 companies. Meanwhile, airlines will keep moving down the runway, as Southwest Air and American Airlines are due to report on Thursday. General Motors and Ford are also on deck. Here are the big earnings to watch this week:

• Monday: Verizon (before the bell)
• Tuesday: General Motors, Coca-Cola, Comcast, UPS, Spotify (before the bell); Alphabet, Tesla, Mattel (after the bell)
• Wednesday: AT&T (before the bell); Ford, IBM, Chipotle Mexican Grill (after the bell)
• Thursday: Hasbro, Southwest Air, American Airlines (before the bell)
• Friday: Bristol-Myers Squibb (before the bell)

4. Down in the Delta

Delta Air Lines battled lingering flight disruptions on Monday as the carrier struggled to recover from Friday's global IT outage. The airline canceled more than 4,600 flights from Friday through Sunday, according to aviation data firm OAG, more than any other carrier, and had already canceled another 550 flights, or 15% of its mainline operation, as of early Monday. Delta CEO Ed Bastian apologized and offered travelers frequent flyer miles. American Airlines — which was also affected after cybersecurity giant CrowdStrike experienced a major disruption linked to a botched tech update — said it was nearly back to normal by Saturday. Delta also offered flight attendants extra pay to motivate them to pick up extra shifts.

5. Fading power

SunPower stock collapsed 70% last week, and analysts have largely written the company off as it is on the verge of going out of business. The residential solar installer told dealers that it will no longer support new leases, installations or product shipments. Its stock has lost nearly all its value in the past 12 months, with the shares down 93%, trading at 79 cents on Friday. The sector has been under pressure as high interest rates have depressed demand and left companies with too much product on hand, while political uncertainty could change tax credits.

— CNBC's Alex Harring, Hakyung Kim, Kevin Breuninger, Dan Mangan, Brian Schwartz, Rebecca Picciotto, Fred Imbert, Leslie Josephs and Spencer Kimball contributed to this report.

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