The third quarter ends Wednesday, and on the surface the market will close it out in decent shape. The Nasdaq Composite finished last week at 27,068.72, just below the record it set earlier this month, and the Dow closed above 51,800. Underneath those levels, the conditions are stranger than the index suggests. The Federal Reserve is raising interest rates into record-high stock prices, the 10-year Treasury yield just touched its highest level since the global financial crisis, and oil traded back above $100 a barrel on Monday morning. Over the next several weeks, the market faces four specific tests that will determine whether this year's records extend into year-end, and the first answers arrive within days.

1. The data has to keep the Fed at two more hikes, and no more

On September 16, the Fed raised its benchmark rate by a quarter point to a range of 3.75% to 4%, its first increase since July 2023. Futures markets have since priced in two additional increases this year, one at the October 27-28 meeting and another in December. Stocks have absorbed that path with surprising calm. They have never had to price in a third.

This week's data will decide whether that holds. Wednesday brings the August reading of the PCE price index, the inflation measure the Fed relies on most, and the Cleveland Fed's tracking model has it running near 3.8% from a year earlier, close to double the 2% target. Chair Kevin Warsh has already told markets how he reads numbers like that. At Jackson Hole in late August, he noted that 54% of the goods and services in the PCE basket are rising faster than 3% a year, and he treated that breadth of price pressure as proof the Fed still has work to do. Friday's September jobs report closes the week, with forecasters expecting roughly 100,000 new jobs after 162,000 in August and an unemployment rate holding at 4.1%. Sticky inflation alongside a labor market that cools without cracking would keep the current path intact. Anything hotter opens a conversation about a third hike that stock prices have not yet had.

2. The bond market has raised the bar for owning stocks

The 10-year Treasury yield climbed to 5.18% on Friday, its highest level since the global financial crisis. That number matters well beyond the bond market, because the 10-year sets the base cost of mortgages and corporate borrowing while serving as the yardstick every stock valuation is measured against. When a government bond pays more than 5%, the case for owning expensive equities has to work that much harder.

The strain is already visible beneath the headline level. Since Warsh's Jackson Hole speech sent rates climbing in late August, the S&P 500 has kept grinding higher on the strength of its largest members, while the equal-weighted version of the index, which counts every company the same, and small and mid-cap benchmarks have lagged and lately declined. Last week repeated the pattern, with the S&P 500 up just over 1% even as breadth stayed poor. An index carried by a narrowing group of giant companies can keep setting records, but it operates with less margin for error whenever one of those companies stumbles.

3. Oil has closed the loop into interest rates

Crude is the reason none of this pressure is easing. Brent briefly traded above $100 a barrel early Monday after President Trump rejected an Iranian proposal that would have reopened the Strait of Hormuz, the shipping lane that carries roughly a fifth of the world's oil, for several days. Retail gasoline is averaging close to $4.50 a gallon nationally.

In March, the concern was that the oil shock was becoming a rates shock, with energy inflation boxing in the Fed rather than simply raising prices at the pump. Six months later, that transmission is complete. Elevated energy costs are keeping inflation well above target, which sustains the case for further hikes, and those expectations have helped push Treasury yields to their recent highs. It also means every headline out of the Persian Gulf now moves rate expectations along with oil prices, which is why Monday's Hormuz news knocked stock futures lower before the open.

4. Earnings have to justify record prices at the highest rates in a generation

Third-quarter reporting season begins in mid-October, and it arrives with an unusual burden. With the Fed tightening rather than easing, stock prices can no longer lean on the prospect of cheaper money, so the support has to come from delivered profits. That is especially true for the handful of AI-linked mega-caps holding up the index.

The previews start now. Micron reports this week with analysts expecting its quarterly profit to jump roughly tenfold on AI-driven memory demand, and Nike's results will offer an early look at consumers absorbing $4.50 gasoline. Nvidia, for its part, announced the largest stock buyback in history on Monday, a $150 billion authorization, alongside a new AI safety platform. A buyback of that size can steady a stock, but it cannot substitute for the profit growth that valuations at these levels assume. If the AI leaders deliver, the market's concentration keeps working in its favor. If any of them disappoint with yields above 5%, that same concentration cuts the other way.

Why the next few weeks matter more than the season

History gives the fourth quarter a good reputation, and strategists are already noting that the S&P 500 is entering a seasonal stretch that has produced above-average returns over time. Seasonality describes the average year, though, and this one carries features the averages never had to contend with, including a new Fed chair raising rates into record prices and a live supply crisis at the world's most important oil chokepoint. The grades come in quickly, with the inflation report Wednesday, the jobs number Friday, Micron and Nike in between, and a Fed decision on October 28 behind all of it. Whether the records extend into year-end will depend far less on the calendar's reputation than on how those tests come back.