Investors are heading into next week's Federal Reserve meeting without a clear read on whether the central bank will raise interest rates — a decision that could test a US stock market rally already showing cracks under the weight of rising bond yields.

Rate-Hike Odds Jump on Hot Inflation Data

Bets on a September hike increased Friday after data showed consumer inflation picked up in August, with core CPI — which excludes volatile food and energy prices — rising a hotter-than-expected 0.3%. Fed funds futures were pricing in a roughly 70% chance the central bank raises its benchmark rate from 3.5%-3.75% by a quarter percentage point, according to LSEG data. "The weight is now on a hike in September," said Alicia Levine, chief investment officer at BNY Wealth.

Warsh's Hawkish Shadow

Expectations for a hike have been building since Fed Chair Kevin Warsh's speech last month, which was widely perceived as hawkish. Some investors say Wednesday's decision amounts to a real-time test of Warsh's inflation-fighting credibility, which came under scrutiny following his press conference at the Fed's previous meeting in July. Not everyone is convinced a hike is coming: some investors remain dubious the central bank, which has held rates steady throughout 2026, will actually take that step.

A Rally Already Showing Vulnerability

The benchmark S&P 500 is up roughly 11% so far in 2026, lifted by robust corporate earnings growth fueled substantially by massive AI infrastructure spending. But the index has pulled back recently, now hovering 2.7% below its mid-August all-time high. A broader selloff in the bond market has pushed US Treasury yields to multi-year highs, with the benchmark 10-year yield closing in on the 5% level — a threshold analysts warn could cause further trouble for stocks if breached.

Oil and Iran Add to the Uncertainty

Compounding the picture, investors are also grappling with spiking tensions between the US and Iran, which pushed oil prices above $100 a barrel this week. Cayla Seder, macro multi-asset strategist at State Street, summed up the mood: "We're at a period where there's a lot of uncertainty. You have rising yields, and you have rising expectations of hikes... There is some overall nervousness that has to be priced into the market."

What Happens if the Fed Doesn't Hike

Seder cautioned against reading too much into a possible market rally if the Fed opts to hold steady instead. "We know inflation is above target, we know that unemployment is low," she said. "If the Fed does not hike and you see the market rally off of that, I think that could be an opportunity to fade a little bit. Because there's still this looming environment where, maybe they don't hike in September, but they could at a later date."

What Happens if the Fed Does Hike

If the Fed does raise rates Wednesday, investors said the more important signal will be whether it represents an isolated move or the start of a series of hikes. "If it signals a cycle -- like, hey, we still have work to do... -- I don't think it's going to be great for the market," said Alicia Levine (referred to as BNY's Levine in some reports).

The Broader Financial Sector AI Race

Separately, the report noted that the financial sector itself is racing to deploy AI across lending, payments, fraud detection, and customer service — creating an emerging cybersecurity arms race, as attackers increasingly use AI to probe systems faster and financial institutions turn to AI-based defenses to match that speed. Harshil Mathur, CEO and co-founder of Razorpay, framed the dynamic bluntly at the Global Fintech Fest 2026: "If the threat actor is a model, your defence actor cannot be a human anymore. Your defence actor has to be a model."

The Bigger Picture

With inflation running above target, unemployment still relatively low, Treasury yields creeping toward 5%, and oil prices freshly above $100 amid an active US-Iran conflict, next week's Fed decision arrives at a moment where nearly every major macro signal is pulling in a different direction — leaving markets with a genuinely uncertain setup heading into Wednesday's announcement. For continuing coverage, see the full Reuters Markets report.

With Wednesday's decision shaping up as a real test of both the Fed's credibility and the market's resilience, this week's inflation-driven repricing suggests investors should brace for a choppy, headline-sensitive stretch regardless of which way the central bank ultimately moves.