The Vanguard S&P 500 exchange-traded fund has drawn investors with its industry-low costs, a strategy that has delivered strong results so far.
At a 0.03% expense ratio, VOO costs about $3 per year on a $10,000 investment, matching iShares’ IVV and undercut only by State Street’s SPLG/SPYM at 0.02%.
The fund has delivered a 20.69% gain over the last 12 months, and its total net assets sit near $997 billion as of mid-August 2026.
But the fee comparison that drew millions of investors into VOO says nothing about what the fund holds beneath the ticker symbol.
What VOO holds beneath the S&P 500 label
Technology stocks make up approximately 37% of VOO’s portfolio, with Nvidia, Apple, and Microsoft leading the lineup, Vanguard confirmed.
Depending on the data cut and whether Alphabet’s dual-class share structure is combined, VOO’s 10 largest positions control roughly 36–41% of total assets, meaning about 2% of the names carry more than a third of the weight.
For every $100 invested in VOO, roughly $36 flows into those 10 companies, while the remaining $64 gets divided among more than 500 other names.
That concentration extends beyond stock prices into the earnings that drive them.
Liz Ann Sonders, Chief Investment Strategist at Charles Schwab, noted on the firm’s On Investing podcast in May 2026 that the upward revision in full-year S&P 500 earnings is being powered by just a handful of names.
Just three companies alone, just Alphabet, Amazon, and Meta, explain about 70%, in dollar terms, of the increased earnings expectation for calendar year 2026
A decade ago, the S&P 500’s top 10 stocks held about 19% of the index, meaning concentration has nearly doubled over roughly 10 years, RBC Wealth Management reported in January 2026.
The mismatch between VOO’s sector weight and U.S. economic output
That technology tilt looks dramatically different from the economy the index is supposed to mirror, and the gap keeps widening each quarter.
The Bureau of Economic Analysis (BEA) reported that the Information sector generated just 5.6% of the U.S. gross domestic product in the first quarter of 2026.
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Real estate, the economy’s largest industry by value added, contributed 13.6% of GDP in that same period, and finance and insurance added 8.0%.
Information sector corporate profits jumped from $271 billion in the first quarter of 2025 to $352.5 billion one year later, BEA data showed.
That growth pushed the sector’s share of total domestic corporate earnings from 7.9% to 9.1%, fueling a significant portion of VOO’s recent gain.
But strong earnings and outsized index representation are two distinct things, because cap-weighted positions reflect expectations about future growth, not current economic output.
How the S&P 500’s concentration compares to dot-com-era peaks
Meera Pandit, Executive Director and Global Market Strategist, and Corey Hill, Managing Director and Global Head of Portfolio Insights at J.P. Morgan Asset Management, reported that the S&P 500’s top 10 stocks now account for 40.8% of the index.
That figure surpasses the 26.6% concentration peak reached during the late-1990s technology bubble, the firm noted.
“When valuations are priced to perfection, they are prone to correction,” Pandit and Hill wrote, adding that elevated concentration amplifies the impact on portfolios.
During a 28-session rally from late March to early May 2026, just 10 stocks drove 69% of the S&P 500’s total gains, according to a Nomura return-attribution analysis reported by Investing.com.
The math cuts both ways: the same concentration that amplifies gains on the way up amplifies losses if those names reverse, because a 10% decline in a stock that represents 7% of the index moves the portfolio seven times more than the same decline in a stock weighted at 1%.
Goldman Sachs projects lower S&P 500 returns driven by concentration
David Kostin, Advisory Director at Goldman Sachs, and his team projected in an October 2024 note that the S&P 500 would deliver just 3% annualized returns over the next decade.
That figure would rank in the 7th percentile of 10-year returns since 1930, a steep drop from the 13% average posted over the prior decade.
“If the historical pattern persists, high concentration today portends much lower S&P 500 returns over the next decade,” Kostin’s team wrote.
Goldman’s analysis also indicated that the equal-weight S&P 500 could outperform the cap-weighted version by two to eight percentage points per year.
An equal-weight fund holds the same 500 companies but caps each position near 0.2% of the portfolio, which structurally limits any single sector’s dominance, RBC Wealth Management reported.
The trade-off VOO investors haven’t priced in
VOO’s 0.03% expense ratio still represents a genuine cost advantage, and the fund’s 87.50% five-year total return has rewarded investors who chose low-cost indexing.
But those returns increasingly depend on a narrow cluster of stocks, and online investors have started noticing, with Reddit threads questioning whether the “VOO and chill” strategy carries hidden sector-concentration risk, 24/7 Wall St. reported.
VOO’s 0.03% fee sits within one basis point of the lowest available S&P 500 tracker, so the cost side of the equation is essentially settled.
What’s not settled is whether a roughly 37% technology tilt matches the level of sector risk long-only index investors have typically expected the fund to carry.
Related: VOO shattered a barrier no ETF has cracked, here’s what it means
