From the courtroom to the boardroom, this past week was a whirlwind for the U.S. technology sector, with eight of the nation’s largest tech companies adding a staggering $420 billion to their combined market value in just three trading days. By the end of the week, these so-called megacaps—companies like Alphabet, Apple, Microsoft, Nvidia, Tesla, Amazon, Meta, and Broadcom—had reached a cumulative valuation of $21 trillion, a figure that now accounts for a record-breaking 36% of the S&P 500, according to CNBC.
What drove this massive rally? Much of the action centered around Alphabet, Google’s parent company, which saw its shares rocket up 9% on Wednesday, September 3, 2025. The surge followed a pivotal ruling in Google’s long-running antitrust case. U.S. District Judge Amit Mehta, presiding over the high-profile case, stopped short of ordering a breakup of Google or forcing it to sell its Chrome browser. Instead, Judge Mehta required Google to share its search data with competitors—a far narrower remedy than many had expected. The ruling was seen as a relief for investors, who had feared harsher penalties might be on the table.
According to Cryptopolitan, the news sent Alphabet’s stock up more than 10% for the week, while Apple’s shares also benefited, climbing 3.2%. The reason? The ruling allows Apple to maintain its lucrative arrangement with Google, which pays billions each year to remain the default search engine on iPhones. This partnership, now preserved, was a key concern for both companies as regulators scrutinized Big Tech’s market power.
Analysts at Wedbush Securities captured the mood in a note to investors, writing that the decision “removed a huge overhang” from Google’s stock and cleared a “black cloud worry” from Apple’s prospects. They also pointed out that the ruling could pave the way for a deeper artificial intelligence partnership between the two giants, involving Google’s Gemini AI model. “This now lays the groundwork for Apple to continue its deal and ultimately likely double down on more AI related partnerships with Google Gemini down the road,” Wedbush wrote, as reported by CNBC.
The Department of Justice has targeted Big Tech since 2020, launching antitrust actions against Google, Apple, Amazon, and Meta. Google’s defeat in the DOJ trial about a year ago was widely seen as the most significant antitrust decision in the tech sector since the Microsoft case of the late 1990s. But Judge Mehta’s remedy this week reflected a market transformed by the rise of generative AI. He cited OpenAI, Anthropic, and Perplexity as new competitors challenging Google’s dominance, remarking that these technologies “may yet prove to be game changers.”
Even as Alphabet celebrated its U.S. legal reprieve, it faced a separate setback in Europe. On Friday, September 5, the European Union fined Alphabet €2.95 billion (about $3.45 billion) for anti-competitive behavior in the ad tech market. Yet, as CNBC noted, investors shrugged off the penalty, and Alphabet’s shares remained stable.
Meanwhile, the AI boom was a direct catalyst for another tech rally—this time for Broadcom. After reporting stronger-than-expected earnings on Thursday, September 4, 2025, CEO Hock Tan announced a $10 billion deal with a new customer. Several analysts, as well as The Financial Times, identified that customer as OpenAI. Broadcom, already a supplier of custom AI chips to Google, Meta, and ByteDance (the parent company of TikTok), saw its shares leap 13% for the week. Over the past year, Broadcom’s stock has soared 120%, propelling its market value to around $1.6 trillion and earning it a seat at the trillion-dollar table.
Barclays analysts were bullish in their assessment, writing, “The company is firing on all cylinders with clear line of sight for growth supported by significant backlog.” They maintained their buy rating and raised their price target for Broadcom, reflecting the company’s strong momentum.
Not all tech giants, however, joined the party. Nvidia, the world’s most valuable company with a market cap exceeding $4 trillion, saw its shares fall 4% over the week. This marked Nvidia’s fourth straight weekly decline, despite its stock being up 56% over the past year. There was no clear catalyst for the decline, but the dip stood out amid the broader tech rally.
Microsoft also continued its recent slide, with shares falling for a fifth consecutive week. Still, Microsoft’s stock remains up 21% over the last 12 months, underscoring the resilience of the company despite short-term volatility.
Tesla, meanwhile, has had a challenging year, with its shares down 13% in 2025 due to declining sales and mounting competition from lower-priced Chinese electric vehicles. The company’s aging EV lineup has added to the pressure. But this week brought a reversal of fortune: Tesla’s stock climbed 5%, largely on the back of Friday’s announcement of a proposed new pay plan for CEO Elon Musk. The plan, potentially worth up to $1 trillion and split into 12 payout tranches, would only begin to pay out if Tesla nearly doubles its market capitalization to $2 trillion.
Chairwoman Robyn Denholm explained the rationale behind the plan in an interview with CNBC’s Andrew Ross Sorkin, stating it was designed to keep Musk, who remains the world’s richest person, “motivated and focused on delivering for the company.” For Tesla, the move is seen as an effort to retain its high-profile leader and incentivize long-term performance, even as the company faces stiff headwinds.
With all these developments, the eight trillion-dollar tech companies now represent an unprecedented concentration of market power. As Howard Silverblatt, senior index analyst at S&P Dow Jones Indices, put it in an email to CNBC, “there are no comparisons.” The sheer scale of these companies—and their ability to move markets on the back of courtroom decisions, regulatory fines, or blockbuster deals—underscores just how central they have become to the U.S. economy and global financial markets.
For investors and observers alike, this week served as a vivid reminder that in today’s tech-driven world, fortunes can shift in a matter of days, and the interplay between regulation, innovation, and leadership remains as dynamic—and unpredictable—as ever.
