One of the most crucial weeks of third-quarter earnings season starts Monday - giving corporate America a chance to shake the bad vibes out of the stock market.

According to FactSet, some 36% of S&P 500 SPX companies, or 179 in total, will report quarterly results this week. Headliners include big names like Amazon.com (AMZN), Alphabet (GOOGL) (GOOG) and Microsoft (MSFT), which the index has depended on for gains. But investors are worried about all sorts of factors right now, from the sustainability of the artificial-intelligence trade, to high gas prices, to bond-market tremors.

Analysts still expect the benchmark index overall to show face-melting profit growth of 29.5% for the third quarter, according to a FactSet report released on Friday. But investors have left less room for error - even for companies whose results surpass Wall Street's estimates.

Luke Rahbari, CEO of Equity Armor Investments, said that next week would be the most important week of the earnings season. Microsoft, Alphabet and Amazon - which together are worth nearly $11 trillion - would likely dictate the market's direction, he noted.

"I think the bar is high for many companies, and with cautious to negative market sentiment, it could be a tricky week," Rahbari said over email.

Around a quarter of the companies in the S&P 500 have reported quarterly results so far, according to FactSet. Of those, 83% have put up earnings per share that have come in better than what analysts expected.

But Jonathan Golub, chief investment strategist at Seaport Research Partners, said those results weren't beating estimates as much as investors would have liked, and companies whose results only narrowly surpassed those expectations were likelier to be shunned by investors.

"It's almost like a miss, because we kind of expect things to be coming in stronger," Golub said. "What's weird is you have these insane growth numbers."

Ken Mahoney, CEO of Mahoney Asset Management, said the harsher reactions showed that "expectations were through the roof and a lot was already priced in."

Wall Street's hopes for strong earnings growth have been one of the main drivers propping up the stock market. But worries over inflation, government deficits, a war with Iran that has driven gas prices higher and Big Tech's colossal spending on the AI build-out - spurred by concerns about the debt being shouldered by CoreWeave (CRWV) and AI players - have weighed on markets. While the S&P 500 is still up 11.4% so far this year, it is down 1.6% over the past month.

When Amazon and Alphabet last reported results, their one-time gains from AI investments led to abnormally large profit increases, which helped push the S&P 500's earnings growth higher overall. Golub said results from the tech giants would be particularly important this week, as those past gains could make for bigger swings in the results. Alphabet and Microsoft report results Wednesday, while Amazon follows Thursday.

Elsewhere, United Parcel Service (UPS), Coca-Cola (KO), Visa (V) and Starbucks (SBUX) are among the key companies whose reports in the week ahead will offer a read on the state of the economy.

Golub said that if you factored out the tech industry and the energy industry - with the latter's financials having benefited from higher oil prices (CL00) (BRN00) - the market is "otherwise pretty average. Not bad, just average."

Earnings for the median S&P 500 company are expected to grow about 10%, Golub noted, "which is kind of very normal. So the weighted number distorts how good things are."