The stock market’s front-runners stumbled in October. Here’s where the smart money is moving now.

October brought a notable reversal for the market's front-runners. Worries about dwindling free cash flows and rising borrowing costs disrupted the artificial-intelligence trade, which had led U.S. stocks higher for much of the year. When the market's strongest performers stumble, it often signals that investors are reassessing how much future growth they are willing to pay for today.

The shift matters because AI-linked names had become a large part of index returns, so weakness there can ripple across broad benchmarks. Free cash flow is a key gauge of a company's ability to fund investment without relying on external financing; when it narrows while borrowing costs rise, the math behind high valuations becomes harder to justify. That combination appears to be driving the rotation.

What to watch: whether cash-flow trends stabilize, how borrowing costs evolve, and whether leadership broadens beyond the AI complex. Sustained rotation would suggest a market leaning less on a single theme, while a quick rebound would indicate the pullback was positioning rather than a change in fundamentals.