The ETF Concentration Problem: Why 60% of Your "Diversified" Portfolio Is 10 Stocks
You hold VAS and VGS. Maybe IVV and NDQ. You think you own thousands of companies across dozens of countries. You feel diversified. You are not.
If you hold a 50/50 split of IVV and NDQ — two of Australia's most popular international ETFs — just 8 stocks make up a third of your entire portfolio. One stock alone (Nvidia) is over 8% of everything you own.
This is not a bug. It is how market-cap-weighted ETFs work. And right now, with market concentration at all-time highs and a cycle shift underway, it matters more than ever.
No fund manager wrote this article. No issuer is paying for placement. Just data.
What You Actually Own
Most investors do not look under the hood. Here is what the most common ETF portfolios actually hold.
Portfolio 1: 50% IVV + 50% NDQ
This is one of the most popular combinations on Australian investing forums. Both ETFs are US-focused, and the overlap is extreme — 9 of the top 10 holdings are identical across both funds.
Stock | Weight in IVV | Weight in NDQ | Combined (50/50) |
|---|---|---|---|
Nvidia | 7.45% | 8.90% | 8.18% |
Apple | 6.68% | 7.10% | 6.89% |
Microsoft | 4.85% | 5.80% | 5.33% |
Amazon | 3.56% | 4.30% | 3.93% |
Alphabet (total) | 5.26% | 4.60% | 4.93% |
Broadcom | 2.61% | 2.50% | 2.56% |
Meta | 2.10% | 2.80% | 2.45% |
Tesla | 1.86% | 2.70% | 2.28% |
Top 8 total | 36.5% |
You think you own 3,900+ stocks (VTS) or 500 stocks (IVV) plus 100 stocks (NDQ). In reality, more than a third of your money is in 8 companies — all US tech or tech-adjacent. If the tech sector corrects, your entire portfolio corrects with it.
Portfolio 2: 40% VAS + 60% VGS
The "boring" two-ETF portfolio that dominates r/AusFinance. The good news: there is zero stock overlap between VAS (Australian) and VGS (international ex-AU). The top holdings span different companies entirely.
Stock | Source | Weight in Portfolio |
|---|---|---|
BHP | VAS | 4.10% |
CBA | VAS | 4.04% |
CSL | VAS | 2.30% |
NAB | VAS | 2.08% |
Westpac | VAS | 2.01% |
Nvidia | VGS | 2.76% |
Microsoft | VGS | 2.72% |
Apple | VGS | 2.53% |
Amazon | VGS | 1.64% |
Meta | VGS | 1.19% |
Top 10 = ~25.4% of portfolio. This is genuinely more diversified than IVV+NDQ. No single stock exceeds 4.2%.
But here is the problem: your sector exposure is still heavily concentrated. VAS is ~33% financials and ~26% materials. VGS is ~25% technology. You have zero exposure to commodities, gold, infrastructure, agriculture, and virtually nothing in emerging markets. We will come back to why this matters.
Portfolio 3: VDHG (All-in-One)
VDHG holds ~90% equities across Australian, international, and emerging market shares. The top 10 stocks still account for approximately 25-30% of the equity portion, driven by the same mega-cap tech names that dominate every market-cap-weighted index.
The all-in-one funds (VDHG, DHHF, GHHF) are better diversified than IVV+NDQ, but they still structurally miss entire asset classes — gold, commodities, infrastructure, and small caps barely feature. For a deep comparison, see our VDHG vs DHHF vs GHHF analysis.
The Concentration Is at All-Time Highs
This is not just an ETF design issue. The US market itself is more concentrated than at any point in history.
As of late 2025, the top 10 stocks in the S&P 500 accounted for 41.4% of the entire index — an all-time record, surpassing even the dot-com peak of ~27% in 2000 (Bespoke Investment Group).
The Technology sector alone is now ~35% of the S&P 500, exceeding its dot-com bubble peak of 34.8%.
Period | Top 10 Weight in S&P 500 | What Happened Next |
|---|---|---|
1960s ("Nifty Fifty") | ~40% | Lost decade for those stocks |
2000 (dot-com peak) | ~27% | Tech crashed 78%, S&P fell 49% |
2015 | ~17.8% | (Normal levels) |
2025 | ~41.4% | ? |
When you buy an S&P 500 ETF today, you are making a historically unprecedented bet on a handful of mega-cap companies. This is not diversification. This is concentration dressed up as an index.
No Sector Leads Forever
Here is the data that should make every concentrated investor uncomfortable.
The chart above shows the best-performing S&P 500 sector each year from 2011 to 2025. The leadership rotates constantly:
Technology led in 2017, 2019, 2020, and 2023 — but was near the bottom in 2022 (-28.2%)
Energy was the single worst or second-worst sector in 7 of 10 years from 2012 to 2021 — then exploded higher to lead in 2021 (+54.6%) and 2022 (+65.7%)
Financials were the largest sector in the S&P 500 in 2002 at 20% of the index — then lost 55% in 2008 and have never recovered their prior dominance
Communication Services (Google, Meta, Netflix) led in 2024 and 2025 — but lost 39.9% in 2022
The Historical Pattern
Every sector that becomes "obviously dominant" eventually mean-reverts:
Sector | Peak Weight | Peak Year | What Followed |
|---|---|---|---|
Energy | ~30% of S&P 500 | 1980 | Fell to 5% by early 2000s |
Technology | ~33% of S&P 500 | 2000 | Crashed to 14% by 2003. Nasdaq fell 78% |
Financials | ~20% of S&P 500 | 2002 | Lost 55% in 2008. Never recovered prior weight |
Energy | ~16% of S&P 500 | 2008 | Fell to 2% by 2020 |
Technology | ~35% of S&P 500 | 2025 | ? |
Research from CFA Institute shows that in periods of high market concentration, the bottom 490 stocks in the S&P 500 outperform the top 10 in 88% of subsequent 5-year periods. The De Bondt & Thaler (1985) study documented mean reversion across decades — prior winners underperform and prior losers outperform.
This does not mean tech will crash tomorrow. But it means that betting your entire portfolio on the sector that has already won for a decade is exactly when concentration risk is highest.
The Cycle Has Already Shifted
You do not need to look at 20-year history. Look at the last 12 months.
Every single commodity, resource, and hard-asset ETF on the ASX outperformed your core portfolio in the 12 months to March 2026.
What Your Core ETF Returned | 1-Year |
|---|---|
VGS (International Shares) | 7.8% |
IVV (S&P 500) | 6.9% |
VDHG (Diversified Growth) | 10.4% |
DHHF (Diversified Growth) | 10.1% |
NDQ (Nasdaq 100) | 11.3% |
VAS (Australian Shares) | 11.5% |
What Your Core ETF Missed | 1-Year |
|---|---|
HGEN (Hydrogen) | 100.8% |
MNRS (Gold Miners) | 92.5% |
URNM (Uranium) | 85.9% |
GDX (Gold Miners) | 77.9% |
ACDC (Battery Tech) | 75.5% |
WIRE (Copper Miners) | 70.8% |
OOO (Crude Oil) | 70.8% |
QRE (AU Resources) | 45.4% |
FUEL (Global Energy) | 40.1% |
FOOD (Agriculture) | 39.4% |
PMGOLD (Physical Gold) | 34.2% |
The top 25 performing ETFs on the ASX over the past year are all commodities, resources, gold, uranium, silver, energy, and metals. Not a single "core" equity ETF made the list.
This is not a prediction. This is what already happened. And if your portfolio was 100% VAS + VGS (or IVV + NDQ), you captured none of it.
The cycle has shifted. Hard assets are leading. The question is whether your portfolio is positioned for it.
Why This Matters: Valuation and Mean Reversion
Markets are cyclical. No asset class outperforms forever. The evidence is overwhelming:
Technology's current weight (~35%) exceeds its dot-com peak. The companies are more profitable today, so the comparison is not exact — but the concentration risk is the same. When a sector is 35% of an index, it does not need to crash for your portfolio to underperform. It just needs to grow slower than everything else.
The last time commodities led was 2004-2007. Energy stocks returned 254% over that decade while the S&P 500 returned 112%. Then energy collapsed. Most investors had zero exposure during the run — and by the time they bought in, it was too late.
The same rotation is playing out now. From 2012-2021, energy was the worst-performing sector in 7 of 10 years. In 2021-2022, it was the best. Gold miners have returned 222% over 5 years. Uranium ETFs doubled in 12 months. Your VAS+VGS portfolio holds precisely none of these.
The pattern repeats every cycle: investors pile into the recent winner (tech), ignore the recent loser (commodities/resources), and then are surprised when leadership rotates.
The Solution: Core + Satellite
You do not need to abandon your core ETFs. VAS + VGS (or VDHG) are excellent foundations. But a foundation is not a complete building.
The core-satellite approach keeps your diversified base while adding targeted satellite positions in the asset classes your core structurally misses.
A Model Approach
Allocation | ETF Examples | Role |
|---|---|---|
Core: 70% | ||
25% Australian Shares | Domestic equity base | |
45% International Shares | Global developed markets | |
Satellite: 30% | ||
8% Gold / Precious Metals | Inflation hedge, portfolio insurance | |
5% Commodities / Resources | Hard asset cycle exposure | |
5% Emerging Markets | Non-developed world diversification | |
5% Infrastructure | Defensive real assets | |
7% Thematic / Megatrend | AI, robotics, defence, clean energy |
For more on building core and satellite allocations, see our Core Portfolio guide and Satellite Portfolio guide.
Why Satellites Work
The purpose of satellite holdings is not to chase last year's winner. It is to own asset classes that behave differently from your core — so that when the cycle rotates (and it always does), part of your portfolio benefits.
Over the last 12 months:
A 70% core (VAS+VGS) / 30% satellite (gold, resources, EM) portfolio would have returned approximately 18-20%
A 100% VAS+VGS portfolio returned approximately 9-10%
The satellites nearly doubled the total return — not because they are better investments, but because the cycle favoured them this time.
For more on what your core ETF structurally misses and how to fill the gaps, see our Build Your Portfolio From Scratch guide.
The Bottom Line
If You Hold... | Your Concentration Risk | What To Consider |
|---|---|---|
IVV + NDQ | Extreme — 33%+ in 8 tech stocks | Replace NDQ with VGS or BGBL for geographic diversification |
VAS + VGS | Moderate — well diversified by stock, but missing entire asset classes | Add 10-20% in satellite positions (gold, commodities, EM) |
VDHG / DHHF | Moderate — good equity spread but zero hard assets | Add 10-15% in satellites outside the all-in-one |
VAS + IVV | High — 100% US on the international side, zero non-US developed | Switch IVV to VGS/BGBL, or add non-US satellites |
The real risk is not that your portfolio drops 50% tomorrow. It is that the next 5-10 years look nothing like the last 5-10 years — and your portfolio is positioned for a cycle that has already passed.
Technology will not lead forever. No sector ever has. The data is unambiguous on this point across 26 years of S&P 500 sector history.
The solution is not to sell your core ETFs. It is to stop pretending they are all you need.
Data sourced from CBOE Australia (performance to 31 March 2026), Novel Investor (S&P 500 sector returns), Bespoke Investment Group (concentration data), issuer websites (Vanguard, iShares, BetaShares), and ReviewETF.
Compare every ETF mentioned in this article at ReviewETF.com.au — fees, performance, and holdings for every ASX-listed ETF.
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