The stock market appears poised for another promising year in 2026, buoyed by transformative megatrends such as artificial intelligence (AI). The S&P 500 index, comprising 500 companies across 11 sectors, is significantly influenced by its largest constituents, particularly in the tech sector. Companies like Nvidia and Alphabet are leading this surge, making their market capitalizations a pivotal factor in the index’s performance.
Recently, the S&P 500 reached new heights, propelled by a notable 16% increase in 2025, surpassing its average annual return since its inception in 1957. The surge in returns aligns with a broader trend where AI has catalyzed substantial growth within the semiconductor, software, and cloud computing industries—a trend expected to continue into the foreseeable future.
For investors contemplating entry into the market with the index at an all-time high, the Vanguard S&P 500 ETF offers an appealing opportunity. This low-cost exchange-traded fund (ETF) mirrors the performance of the S&P 500 and has an expense ratio of just 0.03%, which is significantly lower than the average fee of 0.73% charged by comparable ETFs from other firms. An investment of $10,000 in the Vanguard ETF would incur an annual fee of merely $3.
The S&P 500 is heavily weighted towards the information technology sector, which accounts for 36.1% of the index. This sector includes major players like Nvidia, Microsoft, and Apple, which together are worth $11.9 trillion. Since the AI boom began in early 2023, the S&P 500 has rallied by 78%. Excluding the tech sector, however, the index’s return drops to 52%, underscoring the pivotal role of technology in the current market landscape.
The financial sector, comprising 12.9% of the S&P 500, features major entities such as Berkshire Hathaway and JPMorgan Chase, while the consumer discretionary sector, at 10.5%, includes tech-savvy companies like Amazon and Tesla. The communication services sector also plays a significant role, featuring AI-driven giants like Meta Platforms and Alphabet. The remaining sectors—healthcare, industrials, consumer staples, energy, utilities, real estate, and materials—contribute to the index’s diversification.
Despite the market’s robust performance, potential investors should remain wary of the typical fluctuations that characterize stock investing. Historically, the S&P 500 experiences an average annual decline of at least 5%, with more severe downturns occurring approximately every two and a half years. Major bear markets, defined by peak-to-tect declines of 20% or more, have occurred roughly every six years, with the last one having taken place in 2022. Given this context, barring an unforeseen economic downturn, investors could anticipate a few additional years of favorable returns before facing another significant drop.
Further supportive factors include the ongoing AI boom, projected to generate trillions in value, alongside the Federal Reserve’s gradual interest rate reductions, generally favorable for corporate earnings. Nonetheless, with the S&P 500 currently trading at a historically high valuation, the risk of a correction looms in the near term. To mitigate this risk, a prudent strategy for potential investors could involve starting with a smaller position in the Vanguard S&P 500 ETF and incrementally increasing their investment over time. This approach may help lower the cost basis and provide some cushion in the event of a sharp market sell-off.
