The S&P 500, a benchmark of American stock market health, is comprised of 500 leading companies across 11 sectors. Its rigorous inclusion criteria, including a minimum market capitalisation of $22.7 billion and profitability, ensures a focus on quality. Since its inception in 1957, the index has delivered an impressive average annual return of 10.6%. However, recent geopolitical uncertainty has injected volatility into 2026, with the index currently sitting around 5% below its peak.
The Vanguard S&P 500 ETF (NYSEMKT: VOO) mirrors the S&P 500’s holdings and weighting, presenting investors with a straightforward way to track the index’s performance. The question now is whether the recent dip represents a buying opportunity or a reason to remain cautious.
The S&P 500’s market capitalisation weighting means that larger companies exert greater influence on its overall performance. While diversified across 11 sectors, some hold significantly more sway than others.
Here’s a breakdown of the five largest sectors within the S&P 500:
| S&P 500 Sector | Weighting | Most Valuable Companies |
|---|---|---|
| Information Technology | 32.4% | Nvidia, Apple, Microsoft |
| Financials | 12.5% | Berkshire Hathaway, JPMorgan Chase, Visa |
| Communication Services | 10.5% | Alphabet, Meta Platforms, Netflix |
| Consumer Discretionary | 10% | Amazon, Tesla, Home Depot |
| Healthcare | 9.8% | Eli Lilly, Johnson & Johnson, AbbVie |
Data source: Vanguard. Sector weightings are accurate as of Feb. 28, 2026, and are subject to change.
The remaining six sectors – industrials, consumer staples, energy, utilities, materials, and real estate – contribute the remaining portion of the index’s composition.
The information technology sector boasts a concentration of trillion-dollar giants. Nvidia, Apple, and Microsoft command a combined market capitalisation of $10.9 trillion. Broadcom adds another $1.5 trillion, while Taiwan Semiconductor Manufacturing contributes $1.7 trillion.
