Stocks are closing out September with two trading days left, and while anything could happen, a major reversal that would erase the month’s gains for all major indexes is considered unlikely. To do so would require significant drops: about 183 points off the Standard & Poor’s 500 Index, 702 points from the Dow Jones Industrial Average, more than 1,000 points from the Nasdaq and Nasdaq-100 indexes, and 57 points off the Russell 2000 Index.
Market analysts say that only a dramatic catalyst—such as a war, a Supreme Court decision enabling large tariff increases, or the collapse of a major company or bank—would likely trigger such declines. Historical market crashes like those in 1987 and 2008 were preceded by warning signs months before the actual sell-off.
Last week saw stocks slip slightly. However, heading into October, markets remain at or near record highs. The technology sector continues to dominate. The ten largest companies—including Nvidia, Microsoft, and Apple—now account for nearly $20.7 trillion in value, representing almost 38% of the S&P 500’s total market capitalization.
There is ongoing debate about future performance. The S&P 500 closed Friday at 6,644, up nearly 13% for the year—a level many analysts previously thought would be reached only by year-end. Recently Goldman Sachs and Deutsche Bank raised their targets to 7,000 for late this year or early next year.
Some experts have started to warn that high levels of spending on artificial intelligence may be unsustainable. GQG Partners noted in an August report that this concentration of value among top firms was last seen in October 1970; it was followed by a bear market through much of that decade.
The challenge lies in whether AI investments will generate enough revenue to justify their costs. One estimate cited by The Wall Street Journal suggests that “the money invested in AI infrastructure in 2023 and 2024 alone requires consumers and companies to buy roughly $800 billion in AI products over the life of these chips and data centers to produce a good investment return.”
While some believe markets will continue rising, others caution that corrections are always possible due to unexpected negative events or overconfidence among investors.
In September, communication services led sector gains (with Alphabet and Meta Platforms at the forefront), while materials lagged despite strong performance from gold producer Newmont.
Earlier this year, volatility spiked during what was called the Trump Tariff Panic; between late 2024 and early April, the S&P fell nearly 15%. It has since rebounded sharply—up more than 37% from its April low—and remains close to recent highs.
Analysts caution that another decline of around 10% between now and March is possible given current valuations and uncertainty ahead of third-quarter earnings season. Reports begin soon with Delta Air Lines on October 9th followed by JP Morgan Chase on October 14th.
Carnival is expected to report revenue growth of about $8.1 billion (up over two percent) with earnings per share also increasing modestly; its shares are up nearly twenty-three percent this year. Jefferies shares have risen fifty-eight percent since April but remain down nearly fifteen percent for the year overall. Nike faces challenges amid shifting consumer demand with revenues projected down five percent compared to last year.
As third-quarter results approach and debates continue over market concentration and AI spending risks, investors remain watchful for signs of either continued growth or renewed volatility.
