On Sept. 22 the US stock market split in two. The Nasdaq Composite closed at a record 27,244.28, while the Dow Jones Industrial Average fell 185 points to 51,863.69. The S&P 500 financials index, which groups banks, insurers and brokerages, fell as much as 2.4% during the session and closed at its lowest since July.
What worried investors that day was ‘Muse,’ an AI assistant app from Meta (the parent of Facebook and Instagram). Anyone with a bank account, insurance or subscriptions is a customer in this story, and anyone who owns those companies' shares is an investor in it too.
- Meta's AI assistant does tasks instead of just answering
Meta launched Muse, a personal AI assistant app, on Sept. 8. There is a free version, and according to reports, paid plans cost $20 and $100 a month.
Unlike AI chatbots that stop at answering questions, Muse does what it is told. It sends emails, books trips, and browses the web all the way to completing payments. It keeps working on assigned tasks even after the user closes the app.
- Why did stocks move only two weeks after launch?
What changed in those two weeks were the numbers. Muse became the No. 1 free app on Apple's US App Store and was downloaded 264,000 times in the US on Sept. 19 alone. One tally also found its early downloads outpaced ChatGPT's at launch.
Then on Sept. 21 Meta shares jumped 11.3% to close at $741.25, adding $192 billion in market value in a single day. A ‘neat app’ had become an ‘app lots of people will use.’ Bank and insurance stocks slid one after another on the very next trading day.
- Hassle was someone's revenue
People rarely switch bank accounts. Even if another bank pays more interest, moving is a hassle. They let insurance auto-renew and put off canceling gyms they never go to. This habit is called consumer inertia.
Inertia is free profit for companies. Banks can keep deposit rates low without losing deposits and pocket the difference. Planet Fitness, a US gym chain with low monthly fees, has long relied on ‘ghost members’ who pay $10 to $25 a month but rarely show up, because the effort of calling to cancel feels bigger than the fee going out every month.
- What changes if an AI assistant makes the cancellation call for you?
Here is the next scene investors pictured: an AI assistant moves money to an account paying more interest, cancels unused memberships, renegotiates phone plans, and switches insurance when a cheaper option appears. These are things consumers could do but didn't bother to.
Meta has not announced that it will add these features to Muse. But the market's reasoning is that an assistant that writes emails and even makes payments isn't far from making cancellation calls. Goldman Sachs' trading desk also noted that day that industries relying on recurring billing, add-on products and customer apathy face a serious hit.
If a cancellation call becomes a one-sentence command, companies will find it harder to keep deposit rates low or quietly raise premiums. The power to set prices without losing customers, known as pricing power, weakens. That means it costs more to defend the same revenue.
- Which stocks fell, and was it all because of AI?
Based on Sept. 22 closing prices, Planet Fitness fell 9.5%, Charles Schwab, a brokerage with many retail investor clients, fell 6.1%, and insurer Allstate fell 5.5%. JPMorgan, Wells Fargo and Morgan Stanley also slipped, and carrier Verizon and travel booking company Booking Holdings each fell 2.6%.
Not all of it was because of Muse. Allstate disclosed on Sept. 17 an estimated $748 million in catastrophe losses for August, and Planet Fitness had already fallen for five straight trading days before Sept. 22. It is more accurate to say AI worries piled onto stocks that were already weak.
And nothing has actually happened yet. How many people moved their accounts through Muse hasn't been disclosed, and none of it shows up in these companies' earnings. Stocks still fell first because a share price reflects the money a company will earn, not the money it has earned.
- BITPRESS Insight
That day the market began to split corporate profits in two: the share earned because the product is good, and the share earned because customers can't be bothered to leave. The latter isn't listed separately on financial statements, but the AI assistant news put a price tag on it.
That share doesn't disappear; it moves. Interest banks no longer keep stays with depositors, and fees from canceled ghost members stay in consumers' wallets. An analyst at US investment bank Evercore cited transaction revenue sharing, along with advertising and subscriptions, as ways Meta could make money from Muse. The spot that decides where customers switch to could become the new gateway.
So even among bank stocks or subscription stocks, valuations will diverge. For companies customers would still choose after comparing, an AI assistant will actually bring in customers; for companies earning from customers who stayed out of inertia, the assistant will take customers away. When switching gets easy, only companies that win under comparison keep their value.
Sources
https://www.bloomberg.com/news/articles/2026-09-22/meta-s-muse-drags-down-stocks-that-depend-on-consumer-inertia
https://www.investing.com/news/stock-market-news/meta-ai-agent-triggers-heavy-selloff-in-banks-insurers-and-travel-stocks-4911491
https://americanbazaaronline.com/2026/09/22/meta-muse-ai-market-cap-488642/
https://finance.yahoo.com/technology/ai/articles/meta-muse-could-become-most-130637015.html
https://finance.yahoo.com/markets/stocks/articles/nasdaq-hits-record-close-ai-112626254.html
https://www.prnewswire.com/news-releases/august-2026-monthly-release-302882017.html
https://stockanalysis.com/stocks/plnt/history/
Glossary
Consumer inertia — The habit of sticking with what you use because switching is a hassle, even when a cheaper or better alternative exists.
AI assistant (AI agent) — An AI program that goes beyond answering questions and directly carries out tasks such as email, bookings and payments.
Pricing power — The ability to raise prices or keep unfavorable terms without losing customers.
S&P 500 financials index — An index that tracks only the banks, insurers and brokerages among the 500 leading US companies.
Trading day — A day the stock market is actually open, excluding weekends and holidays; the trading day after Monday is Tuesday.
