Vanguard’s S&P 500 ETF (VOO) has become the first exchange-traded fund to surpass $1 trillion in assets under management, a landmark moment for the low-cost index fund industry. The milestone, reached last week, underscores the massive shift of investor capital into passive strategies that track broad market benchmarks.
However, the achievement has also reignited debate about the risks of index concentration and elevated valuations. On Tuesday, the tech-heavy Nasdaq 100 fell over 3% by early afternoon, dragging the S&P 500 down nearly 2% and sending VOO about 1% lower. The selloff in chip and AI-related stocks highlighted the vulnerability of funds heavily weighted toward a handful of mega-cap names.
VOO, which charges a management fee of just 0.03%, has outpaced rival funds like State Street’s SPDR S&P 500 ETF (SPY), which charges 0.09%. BlackRock’s iShares Core S&P 500 ETF (IVV) also charges 0.03% and holds roughly $860 billion. The fee competition among these three nearly identical products has become a key battleground, with VOO’s cost advantage driving its rapid growth.
“This is a key milestone,” said Todd Rosenbluth, head of research at VettaFi. “Investors continue to seek low-cost broad market exposure, and VOO delivers that.” But critics point to the Shiller CAPE ratio, which stood at 42 on Monday—close to levels seen during the late-1990s tech bubble. Despite this, Motley Fool’s David Dierking advised long-term investors not to avoid VOO solely based on valuation, noting that decades-long horizons can weather high entry points.
The debate extends beyond VOO to the choice between S&P 500 trackers and total-market funds like Vanguard’s Total Stock Market ETF (VTI). VTI holds 3,494 stocks versus VOO’s 505, offering exposure to mid- and small-cap names. Both carry a 0.03% expense ratio. Year-to-date, VTI has edged VOO with an 8.71% return compared to VOO’s 8.42%, though VOO has delivered higher average annual total returns over the past decade.
Concentration remains the central risk. The top five holdings—Nvidia, Apple, Microsoft, Amazon, and Alphabet—account for a significant portion of the S&P 500’s market cap. If these tech giants continue to lead, VOO may keep outperforming. But a reversal in sentiment or a sharp decline in valuations could hit VOO harder than more diversified funds. Tuesday’s tech rout served as a cautionary signal.
The $1 trillion milestone reflects deep-seated investor habits: steady inflows into low-cost passive funds, a preference for holding the entire market over stock-picking, and the dominance of a few massive players. VOO now stands as the ultimate example—big, cheap, and nearly impossible for competitors to challenge in the current environment.
