Meta Platforms stock gains on AI app Muse and heavy capex plans

Meta Platforms, Inc. (ISIN US30303M1027) stock is trading at USD 668.57 on Nasdaq as of September 19, 2026, following a rally of about 25 percent over the past 30 days powered by its new AI agent Muse and renewed investor confidence in its long-term growth strategy.

AI agent Muse tops App Store and drives a 25% rally

According to Tickeron on September 18, 2026, Meta Platforms shares climbed roughly 25 percent over the trailing 30 days, rising from about USD 546 on August 19, 2026 to approximately USD 682 on September 17, 2026, with the rebound largely attributed to the September 8 launch of Muse, the company’s consumer AI agent.

The AI push is not only reflected in the stock’s performance but also in app rankings: on September 18, 2026, GuruFocus reported that Muse had surged to the number 1 spot in Apple’s U.S. App Store just over a week after release, outpacing rivals such as OpenAI’s ChatGPT and Google’s Gemini in AI-driven consumer applications.

Capex guidance up to USD 145 billion for 2026

Meta’s AI and infrastructure ambitions are backed by aggressive spending plans. As summarized by MSN on September 18, 2026, the company now guides full-year 2026 capital expenditures, including principal payments on finance leases, to a range of USD 130 billion to USD 145 billion, narrowed from a prior range of USD 125 billion to USD 145 billion first outlined in its Q2 2026 report on July 29, 2026.

The upper end of this revised guidance implies Meta could spend up to USD 20 billion more than the previous lower bound, further cementing its position as a mega cloud and AI operator. For investors, this capex profile is a double-edged sword: it supports AI infrastructure and data center build-out but also keeps free cash flow under pressure compared with a more conservative investment plan.

Valuation signals and insider activity

On the valuation side, Meta still appears modestly undervalued on some fundamental metrics. According to GuruFocus on September 18, 2026, Meta’s current trading price of USD 672.12 stood 21.3 percent below its proprietary GF Value estimate of USD 854.33, suggesting a modest undervaluation relative to intrinsic value expectations from that model.

However, insider behavior sends a more cautious signal. The same GuruFocus analysis notes that Meta insiders have been net sellers over the past 12 months, disposing of USD 209.4 million worth of shares with no insider purchases reported during that period. For long-term shareholders this combination of perceived undervaluation and insider selling underlines the importance of closely watching how AI investments translate into sustained earnings and cash flow.

Market performance and trading levels

Recent trading data show how strong the move has been and where the stock stands now. As of the regular-session close on September 18, 2026, Meta Platforms shares finished at USD 665.75 on Nasdaq, down 2.43 percent for the day, with a market capitalization of USD 1.70 trillion and trading volume of 27.54 million shares, according to price history data cited by MarketBeat.

The one-month and one-week performances are still distinctly positive. As MSN reported on September 18, 2026, Meta traded at USD 680.85, up 25.23 percent over one month and 5.66 percent over one week, while still being only 3.32 percent higher year to date and down 11.95 percent over the prior twelve months, signaling that the recent rally has mainly reversed earlier losses rather than pushed the stock to new highs.

Analyst actions and AI momentum

Analyst sentiment has broadly benefited from the AI narrative. Tickeron notes that the September 8, 2026 launch of Muse was followed by a wave of bullish analyst actions, including a JPMorgan price target increase to USD 820 per share, highlighting rising confidence that Meta can monetize AI across its social platforms and new consumer-facing agents.

While the stock’s roughly 25 percent climb over 30 days shows the market’s enthusiasm for these developments, the modest year-to-date gain and still-negative one-year performance suggest that investors remain sensitive to regulatory, youth-safety and content-moderation risks that were at the center of prior sell-offs mentioned in the Tickeron analysis.

Stock near recent highs, investors watch execution

During the trading session on September 19, 2026, Meta Platforms shares traded in a range between a low of USD 660.80 and a high of USD 694.31 on Nasdaq, with a last quoted price of USD 668.57, which is about 1.2 percent above the session low and still roughly 3.7 percent below the intraday high, according to session data cited by Robinhood.

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