• The major indexes snapped three-day losing streaks Tuesday.
• Uber posts stronger-than-expected second-quarter results.
• Microsoft blames Delta for the airline's slow recovery from the major IT outage.

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

1. Rebound

Stocks partially recovered on Tuesday after seeing losses during the previous three trading days. The Dow Jones Industrial Average inched 0.76% higher, ending the session at 38,997.66. Seeing even greater percentage gains, the S&P 500 increased 1.04% to finish at 5,240.03, and the Nasdaq Composite moved 1.03% higher to finish at 16,366.85. Not only that, Japan's Nikkei 225 saw its best day since October 2008 with a gain of 10.2%. The move comes a day after the benchmark declined 12.4%, experiencing its worst session since Black Monday in 1987. Follow live market updates.

2. Uber-successful

It was a winning second quarter for Uber. Topping Wall Street's estimates for the period, the company posted earnings of 47 cents per share on revenue of $10.7 billion. That's above the 31 cents per share on $10.57 billion in revenue expected by analysts polled by LSEG. In terms of monthly active platform consumers, or MAPCs, Uber reached 156 million for the period after its platform received 2.77 billion trips. That's higher than the same period a year ago, which saw 137 million MAPCs with 2.28 billion trips. What's more, the company's revenue and gross bookings in delivery for the second quarter rose 16%, while gross bookings in the mobility unit increased even more at 23%.

3. War of words

Microsoft, joining CrowdStrike, clapped back at Delta Air Lines. Mark Cheffo, who represents Microsoft, recently sent a letter to attorney David Boies, who represents Delta, saying that Microsoft had offered to help Delta for free after the global IT outage that led to thousands of flight cancellations. According to the letter, Microsoft employees told Delta they could help every day between July 19 and July 23, but the airline refused. Cheffo also took aim at Delta's slower recovery compared with its peers, saying it "apparently has not modernized its IT infrastructure, either for the benefit of its customers or for its pilots and flight attendants." The comments come after Delta said it plans to seek damages from Microsoft and CrowdStrike over potential damages caused by the outage. CrowdStrike has also rejected Delta's claims, with lawyer Michael Carlinsky saying Sunday that the company wasn't responsible for the flight cancellations.

4. Walz-ing in

Vice President Kamala Harris on Tuesday tapped Minnesota Gov. Tim Walz as her running mate for November's election. "Tim is a battle-tested leader who has an incredible track record of getting things done for Minnesota families," Harris wrote in a campaign message to supporters. "I know that he will bring that same principled leadership to our campaign, and to the office of the vice president." Walz also confirmed his acceptance of the position in a social media post, saying he's "all in." Following the announcement, the two made their first public appearance together at a rally in Philadelphia. "I couldn't be prouder to be on this ticket," Walz said at the rally. "Thank you for bringing back the joy."

5. Taking it up a notch

Disney is raising its streaming prices. Beginning in mid-October, most Disney+, Hulu and ESPN+ plans will cost $1 to $2 more per month, per a press release. Disney+ basic will be priced at $9.99, while premium will cost $15.99. Hulu with and without ads will cost $9.99 per month and $18.99 per month, respectively. Even Hulu's most expensive plans, which include live TV channels, will see an increase, costing $6 more per month. Meanwhile, ESPN+ will cost $11.99 per month. These increases come as Disney has been trying to steer its customers toward bundles.

— CNBC's Hakyung Kim, Samantha Subin, Lora Kolodny, Leslie Josephs, Jordan Novet, Rebecca Picciotto and Justine Fisher contributed to this report.

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