S&P 500 Top-10 Concentration Hits 37%, Beating Dot-Com Peak

The S&P 500 has rarely leaned so heavily on so few names. As of June 11, 2026, the top 10 holdings of the SPDR S&P 500 ETF (SPY) — the most-tracked proxy for the index — account for roughly 37.3% of the fund’s market value. That share is meaningfully higher than the 27% peak the same cohort touched during the 2000 dot-com bubble, according to Goldman Sachs research.

All 10 of those stocks have a direct line to the AI buildout: chips, cloud capacity, data center networking, or the platforms that are absorbing the spend. With U.S.–Iran peace headlines pushing futures higher into Monday’s open and Brent slipping near $85 a barrel, the index is heading into a fresh week perched on the same narrow shoulders that carried it to a record close above 7,600 earlier this month.

The 10 stocks that decide where the index goes

Here is the snapshot of SPY’s top holdings as published by stockanalysis.com using State Street’s own disclosure data.

Rank Ticker Company Weight
1 NVDA NVIDIA 7.84%
2 AAPL Apple 6.83%
3 MSFT Microsoft 4.56%
4 AMZN Amazon 3.71%
5 GOOGL Alphabet (Class A) 3.30%
6 AVGO Broadcom 2.88%
7 GOOG Alphabet (Class C) 2.65%
8 META Meta Platforms 1.96%
9 TSLA Tesla 1.77%
10 MU Micron Technology 1.76%
Top 10 total 37.26%
Source: SPY ETF holdings via State Street disclosure, as of June 11, 2026.

Notice how few names actually drive the list. Alphabet appears twice because its two share classes (GOOGL and GOOG) are counted separately, and NVIDIA alone carries more weight than the bottom five names combined. The mix is also one-sided thematically: chips and chip enablers (NVDA, AVGO, MU), hyperscale cloud (MSFT, AMZN, GOOGL/GOOG, META), and AI-adjacent platforms (AAPL, TSLA). The S&P 500’s drift is now tightly coupled to whatever the Nasdaq 100 is doing on any given session.

Why this run is unlike past peaks

Concentration in U.S. equities is not new. Goldman Sachs’ equity strategists, who maintain a century-long dataset of S&P 500 weights, count seven episodes in which the top 10 reached “extreme” levels — including the late-1960s Nifty Fifty era and the dot-com bubble. What is different now is the size of the gap.

S&P 500 Top-10 Concentration vs Historical Peaks Bar chart comparing the current top-10 weight share of the S&P 500 (around 37 percent in June 2026) with the dot-com peak in 2000 (around 27 percent), the COVID 2020 rally, and the 1973 Nifty Fifty era. Top-10 share of S&P 500 market cap 0% 10% 20% 30% 40% 1973 Nifty-Fifty ~22% 2000 Dot-com peak ~27% 2020 COVID rally ~28% Jun 2026 AI Eight 37.3%
Sources: SPY holdings for the 2026 figure; Goldman Sachs Asset Management for historical peaks. Historical values are approximate.

The 2026 figure is roughly 10 percentage points above the dot-com top. That gap matters because the index’s day-to-day behavior is now bound to a smaller set of earnings prints, capital-expenditure plans, and AI demand signals.

The AI thread runs through every name

Behind the weights are the actual AI revenue prints. Broadcom’s Q2 fiscal 2026 8-K reports semiconductor AI revenue of $10.8 billion, up 143% year-over-year, with the company guiding Q3 AI revenue to about $16 billion — growth above 200% YoY. That single line item is now larger than the total quarterly revenue of most S&P 500 members.

NVIDIA’s index weight is the cleanest expression of the AI capex cycle: data center sales, networking through Mellanox, and the Blackwell ramp into the second half of 2026 sit at the top of every hyperscaler’s order book. Microsoft, Amazon, Alphabet and Meta — the four largest U.S. cloud and platform spenders — are simultaneously NVIDIA’s biggest customers and four of the next five names on this list. Micron rounds out the chip block as the high-bandwidth memory supplier for those same GPUs.

What concentration peaks have meant historically

Concentration at this level matters for three reasons.

1) Index returns are not diversified. A passive S&P 500 buyer is not getting “the market” so much as a heavily weighted AI capex basket sleeved inside 490 other holdings. The bottom half of the index can rally and barely move the tape.

2) Forward returns historically moderate. Goldman’s research notes that in five of the seven prior extreme-concentration episodes the index continued higher after the peak — but the two exceptions, 1973 and 2000, marked the start of prolonged bear markets. The base rate cuts both ways.

3) Factor exposures get distorted. When NVDA alone is 7.84% of the cap-weighted index, S&P 500 returns can no longer be cleanly described as “U.S. large-cap equity.” Quality, growth and momentum factor tilts ride along whether the buyer wants them or not.

What to watch from here

The near-term catalysts are concentrated, just like the index. NVIDIA reports next in late August, Broadcom in early September, and Micron’s Q3 FY26 print drops June 24 — each of those releases can move the index by itself. The Fed’s stress-test results on June 24 add a secondary cross-current via the financials, but the dominant signal remains AI capex.

For investors, the practical takeaway is to know what they actually own. A 60/40 portfolio that holds the S&P 500 on the equity side is — today — closer to a 24% AI-capex sleeve than to the diversified U.S. equity allocation textbooks describe. That is neither a buy nor a sell signal. It is a position to size with eyes open.

Sources

Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.

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