Stocks are slumping to start off September. As the focus shifts away from earnings and toward the macro picture, more dour days could be ahead.

As is often pointed out this time of the year, September is traditionally the weakest month for stocks. But simply blaming stock market seasonality oversimplifies the problem.

For the past two months, headlines of better-than-expected earnings have been hitting the tape daily. Indeed, with 97% of the index having reported earnings, S&P 500 companies are pacing for earnings growth of 52%, more than double the 23.1% analysts had expected at the end of June, per FactSet data.

But great earnings-which sent a flurry of stocks higher over the past few months, and helped buoy a 2.6% gain for the S&P 500 in August-are now old news. With the earnings calendar largely silent, investors are forced to shift their attention to macroeconomic data, the Federal Reserve's interest rate path, and war headlines that keep sending oil prices higher.

Scott Rubner, Citadel Securities head of equity and equity derivatives, examined implied moves for the S&P 500 through Sep. 18. Each day that is priced for a larger than average move for the benchmark index is tied to a macro event, such as Friday's looming August jobs report, next week's August inflation report and the Fed decision on Sep. 16.

"After an earnings season dominated by positive surprises, the right tail around the next set of events is less obvious," Rubner writes.

In the past week, rate hike odds for September have soared. Markets are now pricing a 66% chance the Fed raises rates at its next meeting, up from a 40% chance just a week ago, per the CME FedWatch Tool.

This Friday's jobs report could well increase those odds, says Jay Woods, chief markets strategist at Freedom Capital Markets. If the report shows that unemployment rate held flat at 4.1% while average hourly earnings increased, it could suggest to the Fed that the labor market is strong enough to withstand rate increases.

"The hope is for modest job creation, stable unemployment, and contained wage growth," Woods writes. "That would be the Goldilocks scenario. It would not force the Fed's hand, nor scare investors, and keep hopes alive of that dreamy soft landing."

That's just the first hurdle for stocks, though. Then comes an inflation report, which is expected to show price increases accelerated slightly on a monthly basis. That'll be followed by the Fed meeting, with rising bond yields serving as the key backdrop for each event.

As of Tuesday's close, the 10-year Treasury yield was hovering just below 4.8%, its highest level since January 2025. Meanwhile, the 30-year Treasury yield sat at 5.27%, just shy of its highest level since 2007. Any macro data that moves yields higher presents a potential headwind for stocks.

Julian Emanuel of Evercore ISI points out that since the equity bull market began in October 2022, a 10-year Treasury yield of 4.75% or above has proven "noxious to stocks."

A "challenged macro" environment has led Emanuel, who's been among the most bullish strategists on Wall Street this year, to tell clients that the near-term setup is "defensive."

To be clear, Emanuel is not calling for an end to the bull market. Another earnings season will come soon enough, and investors may once again cheer America's profit boom. But the question is what shape the market will be left in after a macro-heavy September comes to an end.