Business News at a Glance

Tech Companies Drag Stock Markets Down Again

Investors pummeled technology company stocks again Tuesday, knocking the Standard & Poor’s 500-stock index down 1.7 percent. The Nasdaq composite, laden with technology stocks, sank 2.9 percent after a flurry of bad news about specific companies metastasized into a broad retreat. The sell-off was ignited when the chip maker Nvidia said it was suspending tests of its self-driving car technology, sending its shares plunging 7.8 percent. Shares of Tesla, a maker of electric-powered vehicles, also were in free fall, plunging 8 percent. Facebook’s shares fell 4.9 percent amid reports that chief executive Mark Zuckerberg would testify before Congress.

Zuckerberg Makes a Date for a Live Chat in Congress

For 10 days, Mark Zuckerberg, Facebook’s chief executive, has been under increasing pressure from lawmakers and regulators to answer questions about the improper harvesting of data of 50 million Facebook users by a British political consulting firm, Cambridge Analytica. Now Zuckerberg plans to go to Washington to explain himself. The chief executive has agreed to testify in at least one congressional hearing over the social network’s handling of customer data, according to people familiar with the decision. Specifically, he plans to appear next month before the House Energy and Commerce Committee, the people said.

Apple Takes Aim at Google at the Head of the Class

Apple unveiled a new iPad aimed at classrooms on Tuesday, along with other education tools, in a bid to catch up to Google for students’ attention — and win more school districts’ dollars. The new 9.7-inch iPad includes a faster processor, Apple said, and supports Apple Pencil, a stylus that previously paired with just its more expensive iPads. The device costs $299 for schools and $329 for consumers, the same as its previous version, and the Apple Pencil was priced at $89 for schools. The company also increased the amount of cloud storage for students and announced new classroom software.

Self-Driving Cars at Uber Come Across New Hurdle

Uber says it is not renewing its permit to test self-driving vehicles in California until police and regulators wrap up an investigation into how one of its autonomous vehicles struck and killed a woman in Arizona last week. The company decided to withdraw its renewal application late last week. The move came to light in a letter that California’s Department of Motor Vehicles sent on Tuesday. The letter informed Uber that its permit expires Saturday and that it will have to address “any follow-up analysis or investigations from the recent crash in Arizona” if it applies for a new permit.

Unsold Clothes Piling Up for Struggling H&M

In the world of fashion retailing, even a small stack of unsold clothes can be a bad sign. H&M, the Swedish fashion retailer, outlined a $4.3 billion stack of unsold inventory in its latest quarterly report Tuesday, prompting questions of whether the company is able to adapt to the fierce competition and changing consumer demands reshaping the global apparel market. Signs of its expanding unsold inventory began emerging last year, when it reported an unexpected quarterly drop in sales. On Tuesday, the company said the pile of unsold stock had grown 7 percent in the past year.

Nickelodeon and Hitmaker Agree to End Partnership

Dan Schneider, the prolific producer who has been Nickelodeon’s most reliable hitmaker for the last two decades, is parting ways with the cable channel. Schneider, a former child actor who appeared in the TV series “Head of the Class” and the comedy film “Better Off Dead,” produced hit shows like “iCarly,” “Drake & Josh,” and “Kenan & Kel” for Nickelodeon. Schneider and his production company Schneider’s Bakery are also responsible for the network’s current biggest hit, “Henry Danger.” However, one of Schneider’s shows, “Game Shakers,” was recently canceled.

Breitbart, Facing Headwinds, Tries a New Tack: Live Events

Breitbart News is taking a step into the live events business. Following the lead of other media companies seeking fresh sources of revenue, the right-wing news and opinion site is set to host its first-ever town hall in suburban New Orleans next month, a panel on privacy and technology with the commentator Ann Coulter and Peter Schweizer, the author of “Clinton Cash.” It is an experiment for a site that has lately been confronting declining web traffic and turbulence in its top ranks.