Investors have navigated September, historically the worst month for stock market returns, with the S&P 500 posting a modest gain of less than 1%. While September is the only month that averages a negative return for the index outside of February, this year's positive close sets the stage for October. The S&P 500 has averaged a 0.9% positive return in October, a performance that, while not matching November or December, signals a potentially significant opportunity for market growth.
The start of the fourth quarter brings a wave of highly anticipated third-quarter earnings reports, particularly from major AI infrastructure providers. Alphabet, Amazon, and Microsoft are expected to report their results in the second half of the month. These disclosures could define the market's direction through the end of 2026, as investors scrutinize how these companies are managing their massive investments in artificial intelligence.
These three technology megacaps are deploying hundreds of billions of dollars to expand AI computing capacity in data centers. To date, the growth rates achieved by their respective cloud computing businesses have validated these expenditures. A key focus for upcoming reports will be whether these companies reveal 2027 capital expenditure guidance. The market reaction could swing sharply based on the extent of planned spending, with potential outcomes ranging from a decline to a surge in valuations.
It is widely assumed that Alphabet, Amazon, and Microsoft will increase their capital expenditures in 2027, though the magnitude remains uncertain. Analysts anticipate significant hikes to capex budgets, justified by continued massive revenue growth in their cloud divisions. Alphabet’s Google Cloud provides a clear benchmark for this trend. In the second quarter, its revenue rose 82% year over year while delivering a 36% operating margin. This performance underscores the commercial viability of heavy investment in cloud capacity where customer demand exists.
Similar momentum is expected from Amazon and Microsoft, which could drive their shares higher. Strong performance from these tech giants would also carry positive implications for key chip providers such as Nvidia, Taiwan Semiconductor Manufacturing, and Broadcom. These semiconductor firms constitute a substantial portion of overall stock market value. If the largest tech companies, which account for more than a third of the S&P 500's value, deliver strong results, they are likely to lift the broader index, potentially making October 2026 a standout month on Wall Street.