World's Largest Companies by Market Cap (September 2026): Nvidia Leads at $5.56 Trillion, Meta Surges 29% to Overtake Broadcom

TradingKey - In September 2026, Nvidia retained its position as the world's most valuable company with a market capitalization of $5.56 trillion, followed closely by Apple, Alphabet Class A, and Microsoft. The biggest change in the global market cap rankings in September was Meta Platforms: the company rose 29%, pushing its market cap to $1.88 trillion and overtaking Broadcom to rank eighth.

The Philadelphia Semiconductor Index rose 9.1% in September, accelerating noticeably after a 1.98% gain in August. However, divergence within the index persisted, with TSMC, SK Hynix, and Micron Technology strengthening, while Broadcom fell 4.3%.

The market's main themes in September revolved around corporate events that had already materialized: Apple completed the concentrated launches of the iPhone 18 Pro and Apple Intelligence; Nvidia added a new share buyback authorization, alongside reports regarding chip policy toward China; SpaceX made progress with the 14th flight test of Starship; Tesla's Robotaxi has not yet been publicly commercialized in Nevada; Amazon's market cap remained below $3 trillion; and Broadcom delivered an earnings report showing the clearest growth in custom ASICs and AI semiconductors.

September Global Market Cap Rankings: Nvidia Remains First, Meta Rises to Eighth

As of September 30, the world's leading companies by market capitalization remain concentrated in AI chips, consumer electronics, cloud computing, and digital platforms.

Nvidia's market cap stood at $5.56 trillion, maintaining its position as global number one; Apple ranked second with a market cap of $4.93 trillion; Google-A ranked third at $4.3 trillion; and Microsoft ranked fourth at $3.85 trillion.

Amazon ranked fifth with $2.71 trillion, TSMC ranked sixth with $2.39 trillion, and SpaceX ranked seventh with $1.98 trillion. Meta Platforms' market cap rose to $1.88 trillion, surpassing Broadcom to move from ninth in August to eighth; Broadcom ranked ninth with $1.69 trillion. Tesla, SK Hynix, and Micron Technology ranked 10th through 12th, respectively.

In terms of monthly performance, Meta Platforms rose 29%, showing the strongest performance among the listed companies; SK Hynix gained 13%, Micron Technology rose 12%, TSMC climbed 11%, Apple increased 6.4%, SpaceX gained 5.1%, and Nvidia rose 4.6%.

On the other hand, Tesla fell 4.6%, Broadcom dropped 4.3%, Amazon declined 3%, and Berkshire-A slipped 0.7%.

Compared to August, Micron Technology's market cap rose to $1.21 trillion, surpassing Eli Lilly and Berkshire-A; Amazon's market cap fell further from $2.80 trillion to $2.71 trillion, remaining below $3 trillion.

Nvidia: Buyback Authorization Expands, China Chip Reports Become Policy Variable

On September 28, Nvidia added a $150 billion share buyback authorization, bringing its remaining balance to $235 billion, which the company expects to execute through fiscal year 2028. This capital allocation event finalized in September serves as part of the context behind its continued status as the world's most valuable company.

Reuters reported on September 27 and 29 that China might allow certain companies to purchase modified chips; meanwhile, Nvidia and AMD lobbied against overly broad restrictions on China. These reports brought export controls, modified chip supplies, and lobbying developments back into the month's pricing framework.

Unlike August, which was driven by second fiscal quarter earnings, market discussions around Nvidia in September covered both the buyback authorization and China chip policy, shifting the corporate narrative beyond mere chip shipment figures.

Meta Launches Consumer AI Agent Muse, Stock Rises 29%

Meta Platforms has officially launched Muse, an AI agent tailored for individual users. This represents the latest implementation of Mark Zuckerberg's vision to embed artificial intelligence into daily life, as well as a major bet by the company in the consumer AI assistant space. Released to U.S. users on September 8, Muse can execute everyday tasks on users' behalf, including online shopping, buying movie tickets, booking sports lessons, and even filling out school activity permission slips. Meta's Chief AI Officer, Alexandr Wang, stated that the core design principle of the product is to be "extremely easy to use for average users".

Meta rose 29% in September, reaching a market capitalization of $1.88 trillion and climbing to eighth place globally, surpassing Broadcom. This was the most notable ranking shift on the September leaderboard, making the consumer AI product launch the corporate event driving the month's largest gain.

Apple: Fall Launch Event Takes Place, Highlighting Hardware and Apple Intelligence

Apple held its autumn product launch event in September 2026, releasing the all-new iPhone 18 series and its first foldable phone, the iPhone Ultra, and completing a concentrated rollout of hardware and Apple Intelligence. John Ternus assumed the role of CEO on September 1, while Tim Cook transitioned to Executive Chairman.

This marks Apple's first hardware release cycle under its new management. Apple's market capitalization rose to $4.93 trillion, continuing to rank second globally. In September, the market's pricing of Apple reflected the products already released and the completed executive transition, rather than an extrapolation of future models or software features.

Semiconductor Sector Recovery Accelerates as Memory and Foundries Lead Gains; Broadcom Pulls Back

The Philadelphia Semiconductor Index rose 9.1% in September. Compared with a 20.61% decline in July and a modest 1.98% gain in August, the recovery expanded significantly in September, indicating that pricing related to AI chips, advanced process nodes, and memory regained strength following a summer adjustment.

Individual stocks did not rise in tandem. TSMC gained 11%, bringing its market cap to $2.39 trillion; SK Hynix rose 13%, with its market cap reaching $1.36 trillion; Micron Technology climbed 12% to a market cap of $1.21 trillion. Nvidia rose 4.6%, remaining at the top of global market capitalization rankings. Meanwhile, Broadcom fell 4.3%, dropping its market cap to $1.69 trillion and seeing its ranking overtaken by Meta Platforms.

Consequently, the semiconductor market in September reflected a structure of "accelerated index recovery, foundries and memory leading gains, and a pullback in leading custom chip stocks." Capital was more concentrated in advanced nodes represented by TSMC, as well as the memory segment represented by SK Hynix and Micron Technology. Although Broadcom posted clear AI semiconductor growth figures, its stock price failed to keep pace with the index during the month.