This Stock Posted the Best Performance in the “Magnificent Seven” in September. (Hint: It’s Not Nvidia.)

Nvidia has been the hottest stock on the planet in recent years, thanks to its dominance in the artificial intelligence (AI) chip market. When investors aimed to bet on AI, Nvidia came up as the obvious choice — and a very wise choice, as the stock has soared 1,000% over five years. But this year, Nvidia hasn't always been the biggest winner. The stock actually slipped in the first quarter, and though it's heading for a 20% annual gain, other AI players have offered investors much better returns in 2026.

How about recently? Well, the month of September, often a difficult one for stocks, proved lackluster for the popular tech stocks known as the "Magnificent Seven," with performance ranging from a loss of 4% for the worst performer, Amazon, to a gain of 5% for the second-best performer, Apple. Nvidia added 3.4% during the month.

But one company stood out in September, posting the best performance of the group -- and its best month since 2022. Let's check out this player and find out if it's still a buy.

Image source: Getty Images.

A laggard over the past year

This particular stock has actually been a laggard compared to other members of the "Magnificent Seven" over the past year. Investors have worried about its significant investments in AI, as it hasn't been among the first to generate major revenue from the technology. In contrast, chip designers and cloud service providers have seen revenue growth since the early days of the AI boom. But, in recent weeks, this company has demonstrated AI progress that has impressed the investment community.

This player is Meta Platforms (NASDAQ:META), a stock that soared 26% in the month of September.

AAPL data by YCharts

You might know Meta best for its social media platforms, as it owns some of the most popular ones around, from Facebook to Instagram. In fact, 3.6 billion people around the world use at least one of Meta's social media apps every day. This popularity prompts advertisers to turn to Meta in order to reach us where they can find us, and as a result, advertising has become the company's main revenue driver.

This is important because Meta's social media strengths have helped it build a highly profitable business, giving it the financial position to invest in an area it hopes will supercharge growth in the coming years -- and that's AI. Meta invests billions of dollars annually to build out its own data centers and develop large language models to power its AI offerings.

Rivaling ChatGPT

And a recent launch is what prompted investors to cheer. In early September, Meta released its Muse personal AI agent, powered by its Spark family of large language models. Muse had 730,000 downloads in the five days following its release, CNBC reported, citing Sensor Tower data. And on Sept. 18, Muse surpassed OpenAI's ChatGPT to become the No. 1 iOS free app in the U.S., according to CNBC.

Muse can be used to a certain extent for free, but the company also offers subscriptions for those with greater usage needs.

In the past, Meta has said it aims to create AI for all its users, and this can be seen as a major step in that direction. This may be monetized through subscriptions and even related products and services. So investors see the Muse launch as an important milestone in the quest to generate significant revenue from the company's AI investments.

Does this make Meta a stock to buy now? Meta trades at 23x forward earnings estimates, up from less than 18x just weeks ago, so the stock has definitely become more expensive. Still, the current price remains reasonable considering Meta's well-established business and its progress in AI. Meanwhile, investors may continue to pile into this player as they look for fresh AI investments -- ones that haven't soared as much as others in recent months.

But whether investors favor Meta in the near term or not, this stock is a great one to buy and hold for the long haul.

Adria Cimino has positions in Amazon and Tesla. The Motley Fool has positions in and recommends Alphabet, Amazon, Apple, Meta Platforms, Microsoft, Nvidia, and Tesla. The Motley Fool has a disclosure policy.