If 2023 was the tech industry’s year of the A.I. chatbot, 2024 is turning out to be the year of A.I. plumbing. It may not sound as exciting, but tens of billions of dollars are quickly being spent on behind-the-scenes technology for the industry’s A.I. boom.

Companies from Amazon to Meta are revamping their data centers to support artificial intelligence. They are investing in huge new facilities, while even places like Saudi Arabia are racing to build supercomputers to handle A.I. Nearly everyone with a foot in tech or giant piles of money, it seems, is jumping into a spending frenzy that some believe could last for years.

Microsoft, Meta, and Google’s parent company, Alphabet, disclosed this week that they had spent more than $32 billion combined on data centers and other capital expenses in just the first three months of the year. The companies all said in calls with investors that they had no plans to slow down their A.I. spending.

In the clearest sign of how A.I. has become a story about building a massive technology infrastructure, Meta said on Wednesday that it needed to spend billions more on the chips and data centers for A.I. than it had previously signaled.

“I think it makes sense to go for it, and we’re going to,” Mark Zuckerberg, Meta’s chief executive, said in a call with investors.

The eye-popping spending reflects an old parable in Silicon Valley: The people who made the biggest fortunes in California’s gold rush weren’t the miners — they were the people selling the shovels. No doubt Nvidia, whose chip sales have more than tripled over the last year, is the most obvious A.I. winner.

The money being thrown at technology to support artificial intelligence is also a reminder of spending patterns of the dot-com boom of the 1990s. For all of the excitement around web browsers and newfangled e-commerce websites, the companies making the real money were software giants like Microsoft and Oracle, the chipmaker Intel, and Cisco Systems, which made the gear that connected those new computer networks together.

But cloud computing has added a new wrinkle: Since most start-ups and even big companies from other industries contract with cloud computing providers to host their networks, the tech industry’s biggest companies are spending big now in hopes of luring customers.

Google’s capital expenditures — largely the money that goes into building and outfitting data centers — almost doubled in the first quarter, the company said. Microsoft’s were up 22 percent. Amazon, which will report earnings on Tuesday, is expected to add to that growth.

Meta’s investors were unhappy with Mr. Zuckerberg, sending his company’s share price down more than 16 percent after the call. But Mr. Zuckerberg, who just a few years ago was pilloried by shareholders for a planned spending spree on augmented and virtual reality, was unapologetic about the money that his company is throwing at A.I. He urged patience, potentially for years.

“Our optimism and ambitions have just grown quite a bit,” he said.

Investors had no problem stomaching Microsoft’s spending. Microsoft is the only major tech company to report financial details of its generative A.I. business, which it said had contributed to more than a fifth of the growth of its cloud computing business. That amounted to $1 billion in three months, analysts estimated.

Microsoft said its generative A.I. business could have been even bigger — if the company had enough data center supply to meet the demand, underscoring the need to keep on building.

The A.I. investments are creating a halo for Microsoft’s core cloud computing offering, Azure, helping it draw new customers. “Azure has become a port of call for pretty much anybody who is doing any A.I. project,” Satya Nadella, Microsoft’s chief executive, said on Thursday.

(The New York Times sued Microsoft and its partner, OpenAI, in December, claiming copyright infringement of news content related to their A.I. systems.)

Google said sales from its cloud division were up 28 percent, including “an increasing contribution from A.I.”

In a letter to shareholders this month, Andy Jassy, Amazon’s chief executive, said that much attention had been paid to A.I. applications, like ChatGPT, but that the opportunity for more technical efforts, around infrastructure and data, was “gigantic.”

For the computing infrastructure, “the key is the chip inside it,” he said, emphasizing that bringing down costs and wringing more performance out of the chips is key to Amazon’s effort to develop its own A.I. chips.

Infrastructure demands generally fall into two buckets: First, there is building the largest, cutting-edge models, which some A.I. developers say could soon top $1 billion for each new round. Chief executives said that being able to work on developing cutting-edge systems, either directly or with partners, was essential for remaining at the forefront of A.I.

And then there is what’s called inferencing, or querying the models to actually use them. This can involve customers tapping into the systems, like an insurer using generative A.I. to summarize a customer complaint, or the companies themselves putting A.I. directly into their own products, as Meta recently did by embedding a chatbot assistant in Facebook and Instagram. That’s also expensive.

Data centers take time to build and outfit. Chips face supply shortages and costly fabrication. With such long-term bets, Susan Li, Meta’s finance chief, said the company was building with “fungibility.” It wants wiggle room to change how it uses the infrastructure, if the future turns out to be not exactly what it expects.

One afternoon last month, Chad Nedohin, a part-time pastor and die-hard supporter of Donald J. Trump, put on a pirate costume, set up his microphone and recited a prayer.

Mr. Nedohin was opening his latest livestream on the right-wing video site Rumble, where he has about 1,400 followers who share a devotion to Trump Media & Technology Group, the former president’s social media company.

“Faith comes from hearing — that is, hearing the good news about Christ,” said Mr. Nedohin, 40, his face framed by fake dreadlocks under a pirate-style hat.

Mr. Nedohin and his viewers were waiting for the results of a merger vote that would determine whether Mr. Trump’s company could start selling stock on Wall Street. Soon the news about Trump Media arrived via an audio feed: It was going public.

Mr. Nedohin raised his arms in celebration. A few minutes later, he cut to a video of a rocket blasting into the sky, with Mr. Trump photoshopped onto it. “We are holding Trump stocks,” he declared. “We are now financial investors in him.”

Mr. Nedohin is one of hundreds of thousands of amateur investors who own shares of Trump Media, convinced that its sole platform, Truth Social, will become one of the world’s most popular and profitable social media sites. In recent months, tens of thousands of Trump fans have tuned into Mr. Nedohin’s webcasts, where he exhorts viewers to invest in the company, arguing that “Trump always wins in the long run.”

The enthusiasm from Mr. Nedohin and other Trump supporters has turned Trump Media into the latest “meme stock,” driven more by internet hype than business fundamentals. In the public markets, these amateur investors have found themselves pitted against professional short sellers, specialist investors who bet that stocks will fail, as well as frantic day traders looking for a quick profit.

As a result, Trump Media’s stock price has swung wildly, sometimes dropping as much as 18 percent or rising as much as 28 percent in a single day. The company is “a meme stock on steroids,” one analyst recently wrote.

The stock’s unpredictable swings have major implications for Mr. Trump’s finances. The presumptive Republican presidential nominee owns more than $4 billion in Trump Media shares, including recently awarded bonus shares — a potential lifeline as he faces steep legal bills tied to the cases against him. The stock’s volatility could add hundreds of millions of dollars to his paper wealth — or vaporize it.

A Canadian citizen, Mr. Nedohin cannot vote for Mr. Trump in November. But he owns more than 1,000 shares in Trump Media, which are trading at about $36, down roughly 50 percent from its peak in March.

Mr. Nedohin began buying the shares in late 2021, after Digital World Acquisition Corporation, a publicly traded shell company, announced plans to merge with Trump Media. Digital World was trading at $93 a share at the time.

Once the merger was final on March 25, Trump Media began trading on Wall Street, and the original Digital World shares were converted into Trump Media stock under the ticker DJT.

Mr. Nedohin said he had held on to his shares and didn’t plan to sell. On the livestream, he interacts with viewers who use screen names like GOATPOTUS, urging them to keep the faith even when prices fall. “Don’t freak out,” he said on a recent show.

Truth Social “has the potential to easily eclipse Twitter,” the app now known as X, Mr. Nedohin said in an interview. “I’m not concerned about my investment whatsoever.”

Mr. Nedohin doesn’t like the term “meme stock” and prefers “populist retail investment.” But if he’s wrong about his bet, the financial impact on his viewers and Trump Media’s other investors could be devastating, given the risks of these volatile stocks.

By traditional metrics, Trump Media is not a successful business. The company reported $4 million in revenue last year and $58 million in losses. Compared with mainstream social sites, Truth Social has a minuscule audience — 1.5 million people visited the site last month, according to data from Similarweb, a small fraction of the 75 million who logged on to X.

Still, loyal investors like Mr. Nedohin are one reason Trump Media’s stock now trades at a valuation roughly equivalent to that of established companies like Wendy’s and Western Union. This month, Devin Nunes, Trump Media’s chief executive and a former Republican congressman, cited the enthusiasm of retail investors as a sign of the company’s strength.

Any suggestion that those traders might lose money amounts to “punching down at hundreds of thousands of everyday American retail investors,” Shannon Devine, a Trump Media spokeswoman, said in an email.

From his home in Edmonton, Alberta, Mr. Nedohin works as an engineer, calculating mechanical stress on pipes. But his passion is ministry: Although not ordained, he said, he has taken part-time gigs at local churches, leading worship groups as a nondenominational lay pastor. He’s also a guitarist, with a portfolio of original Christian songs, some of which have played on Canadian radio.

Before Truth Social, he said, he sometimes posted on Facebook but never got much traction. He craved an alternative.

In 2021, Mr. Trump co-founded Trump Media after he was kicked off Twitter for his incendiary posts before the U.S. Capitol riot on Jan. 6. A year later, Truth Social went live, managed by two former contestants on “The Apprentice.”

Mr. Nedohin had been a fan ever since Mr. Trump glided down the escalator at Trump Tower in Manhattan to announce his 2016 campaign. He considers the former president a supporter of Christian values, and believes the 2020 election was stolen from him.

Mr. Nedohin created a Truth Social account in May 2022 and soon found a community that shared his two main interests: Christianity and Digital World’s stock.

“I’ve never met such an amazing group of people who are so happy to have freedom of speech,” he said.

But Truth Social was glitchy, and Mr. Trump took months to post his first message. In 2022, the two “Apprentice” contestants left Trump Media after the Securities and Exchange Commission opened an investigation into the Digital World merger.

That inquiry delayed Trump Media’s plans to go public, and the price of Digital World’s stock dropped. Mr. Nedohin was concerned. But in the spring of 2022, he said, he received a message from God.

“You ask him to move a mountain, and sometimes he hands you a shovel,” Mr. Nedohin said. This time, he said, “that little voice inside” told him to start a podcast.

Mr. Nedohin started the Rumble show, “DWAC’d Live!” — a reference to Digital World’s stock symbol. On the show, he tried to mobilize Truth Social’s users, urging them to send letters to Congress protesting the S.E.C.’s investigation.

He adopted the pirate persona to drive attention, he said, calling himself “Captain DWAC” on the livestream. On Truth Social, he emerged as what passes for an influencer, with 6,600 followers.

Mr. Nedohin’s advocacy got the attention of Eric Swider, a Trump Media board member and former Digital World chief executive, who appeared on “DWAC’d Live!” last year.

“Make sure that you help get the word out there,” Mr. Swider said on the show, adding that “we’re very, very grateful for your assistance.”

In July, Digital World settled with the S.E.C. for $18 million, paving the way for the merger with Trump Media to be approved last month. Mr. Nedohin was ecstatic.

But the drop in Trump Media’s share price has caused consternation online, with some Truth Social users complaining that they have lost money. Much of the frustration has been directed at short sellers.

Trump Media posted instructions for shareholders on its website explaining how to prevent brokerage firms from lending shares to short sellers. Last week, Mr. Nunes wrote a letter to the Nasdaq, where the stock is listed, complaining about “potential market manipulation.” He followed that up with letters on Tuesday to the Republican chairs of several congressional committees. Mr. Trump previously warned that short sellers could “get hurt very badly.”

“As a Christian, I don’t believe in shorting,” Mr. Nedohin said. “I believe in only building for the positive.”

He remains fully committed to Truth Social. During the S.E.C. protest, he said, he returned to X, hoping to raise awareness about the campaign. Now that Trump Media is a public company, “I will never need to reach any of the people that are on there,” he said.

As his livestream ended, Mr. Nedohin deleted his X account.

Audio produced by Adrienne Hurst.

The federal government’s main auto safety agency said on Friday that it was investigating Tesla’s recall of its Autopilot driver-assistance system because regulators were concerned that the company had not done enough to ensure that drivers remained attentive while using the technology.

The National Highway Traffic Safety Administration said in documents posted on its website that it was looking into Tesla’s recall in December of two million vehicles, which covered nearly all of the cars the company had manufactured in the United States since 2012. The safety agency said it had concerns about crashes that took place after the recall and results from preliminary tests of recalled vehicles.

The agency also published an analysis that found that there had been at least 29 fatal accidents involving Autopilot and a more advanced system that Tesla calls Full Self-Driving from January 2018 to August 2023. In 13 of those fatal accidents, the fronts of Teslas hit objects or people in their path.

The investigation of Tesla’s recall and the new data about crashes adds to a list of headaches for Tesla, the dominant electric-vehicle maker in the United States. The company’s sales in the first three months of the year fell more than 8 percent from a year earlier, the first such drop since the early days of the coronavirus pandemic.

Tesla announced in December that it would recall its Autopilot software after an investigation by the auto safety agency found that the carmaker hadn’t put in place enough safeguards to make sure the system, which can accelerate, brake and control cars in other ways, was used safely by drivers who were supposed to be ready at any moment to retake control of their cars using Autopilot.

In its analysis of Tesla crash data, the safety agency found that when the company’s cameras, sensors and software did not spot obstacles in the car’s path and drivers did not compensate for that failure quickly enough the consequences were often catastrophic.

In one case, a child who had just gotten off a school bus in March 2023 in North Carolina was hit by a Tesla Model Y traveling at highway speed. He had serious injuries. “Based on publicly available information, both the bus and the pedestrian would have been visible to an attentive driver and allowed the driver to avoid or minimize the severity of this crash,” the safety agency said.

It is not clear how often Tesla’s cars are involved in accidents while Autopilot and Full Self-Driving are in use, the agency said, because the company is not aware of every crash involving its cars. The safety agency added that Tesla was an outlier in the auto industry by discouraging drivers to engage with an autopilot system that isn’t equipped for many situations.

Tesla is facing several lawsuits from individuals who claim that the system is defective, and that its design contributed to or is responsible for serious injuries and deaths.

The December recall, which entails a wireless software update, includes more prominent visual alerts and checks when drivers are using Autopilot to remind them to keep their hands on the wheel and pay attention to the road. The recall covers all five of Tesla’s passenger models — the 3, S, X, Y and Cybertruck.

Tesla did not respond to a request for comment.

The auto safety agency also said Friday that it took issue with Tesla’s decision to allow customers to opt in to the recall and let them undo the changes. Tesla also appeared to include other updates that addressed issues related to the recall that the company and the safety agency had not agreed on in advance.

Tesla and its chief executive, Elon Musk, have long chafed at criticism of Autopilot and Full Self-Driving. They have argued that the systems, neither of which allow cars to drive themselves, make its cars safer and have blamed drivers for any crashes or problems.

The carmaker has been under the scrutiny of safety regulators for other issues, too.

Last week, the auto safety agency said Tesla had agreed to recall nearly 4,000 Cybertruck pickups. The agency said the way soap had been used as a lubricant during the assembly of the truck could lead to the accelerator pedal’s becoming stuck. The carmaker is not aware of any injuries or accidents linked to that defect.

In February, Tesla recalled more than two million vehicles because the font size on a warning lights panel was too small.

The company is struggling to hold on to its dominance in the electric-vehicle market as newer and more established automakers introduce new models around the world. Tesla’s market share in the U.S. electric-vehicle market fell to 51 percent in the first quarter, down from 62 percent a year earlier.

Mr. Musk told employees this month that Tesla would cut more than 10 percent of its work force. Two senior executives also announced that they were leaving the company.