-- U.S. edged higher Tuesday, amid cautious trading on a week dominated by Big Tech earnings.

Here are some of the biggest premarket U.S. stock movers today:

• Apple (NASDAQ:) stock fell 0.2% after the company’s iPhone sales in China plummeted by 19% during the March quarter, according to data from Counterpoint Research, marking the device's poorest performance in the region since the onset of Covid around 2020.

• Amazon (NASDAQ:) stock rose 0.5% after the e-commerce giant launched a new grocery delivery subscription in the United States for members of its Prime program and customers who are recipients of the government food assistance benefits.

• General Motors (NYSE:) stock rose 5.1% after the auto giant reported a robust first quarter in 2024, with earnings and revenue surpassing expectations and the company raising its full-year guidance.

• PepsiCo (NASDAQ:) stock fell 0.2% despite the soft drinks giant beating quarterly earnings and revenue expectations, despite a recall of some Quaker Foods cereal and bars that dented U.S. volumes.

• Service (NYSE:) stock rose 1.1% after the delivery firm reported first-quarter profit above estimates as cost cuts partly offset subdued demand for small-package delivery.

• JetBlue (NASDAQ:) stock fell 8.9% after the low-cost airline lowered its 2024 revenue forecast, adding second-quarter revenue would likely drop as much as 10.5% on the year.

• Spotify (NYSE:) stock soared 8% after the music streaming company reported its gross profit crossed E1 billion in a quarter for the first time, despite quarterly monthly active users coming in below estimates.

• Affirm (NASDAQ:) stock fell 0.2%, with the fintech lender starting to offer "buy now, pay later" loans for elective medical procedures, in a major push beyond its core e-commerce market.

• Cadence Design (NASDAQ:) stock fell 6.7% after the chip design software maker forecast second-quarter revenue below expectations.

• Roblox (NYSE:) stock rose 4.4% after JPMorgan upgraded its stance on the gaming platform to ‘overweight’ from ‘neutral’, citing significant monetization opportunities.