The largest ETF by amount of money invested in them have a lot more focus on United States Stock market exposure than any other asset class.

If you want to diversify your holdings in the market with exposure to commodities, stocks and bonds, the most diversified portfolio would suffice with investing < 20% each in 5 ETF’s.

SPY SPDR S&P 500 89.9 US equity

GLD SPDR Gold 58.0 Commodities

EEM iShares MSCI Emerging Markets 47.5 International equity

VWO Vanguard Emerging Markets 44.4 International equity

EFA iShares MSCI EAFE 36.8 International equity

IVV iShares S&P 500 25.8 US equity

QQQ PowerShares QQQ 22.1 US equity

TIP iShares Barclays TIPS Bond 19.4 US fixed income

VTI Vanguard Total Stock Market 18.2 US equity

IWM iShares Russell 2000 17.5 US equity

LQD iBoxx $ Investment Grade Corporate Bond 13.1 US fixed income

IWF iShares Russell 1000 Growth 12.6 US equity

MDY SPDR S&P MidCap 400 12.2 US equity

EWZ iShares MSCI Brazil 11.7 International equity

AGG iShares Core U.S. Aggregate Bond 11.2 US fixed income

SLV iShares Silver 10.8 Commodities

IWD iShares Russell 1000 Value 10.7 US equity

IJH iShares S&P 400 MidCap 9.3 US equity

BND Vanguard Total Bond Market 9.0 US fixed income

DIA SPDR Dow Jones Industrial Average Trust 8.7 US equity