Invesco PowerShares has launched four new global commodities ETFs that seem positioned to battle for assets with existing Market Vectors portfolios targeting the hard assets sector. The new ETFs cover the Agriculture, Coal, Steel and Gold and Precious Metals sectors.

The new PowerShares are based on NASDAQ OMX global sector indexes, whereas Market Vectors uses a variety of index providers for its global hard assets ETFs. The Market Vectors Coal ETF (NYSEArca: KOL) is based on the Stowe Coal Index. The Market Vectors Agribusiness ETF (AMEX: MOO) tracks the Deutsche Boerse's DAXglobal Agribusiness Index. The Market Vectors Gold Miners ETF (AMEX: GDX) tracks the AMEX Gold Miners Index, while Market Vectors Steel ETF (AMEX: SLX) tracks the AMEX Steel Index.

The underlying indexes create differences between the two fund families' holdings, and the largest difference between any of the four similar funds is in the steel portfolios, where only two of the top 10 holdings in each fund are duplicated: Mittal Steel Company and POSCO.

In the case of the PowerShares Global Agriculture (NasdaqGM: PAGG), it mirrors Market Vector's MOO much more closely, with both funds having the same top five holdings, as of  August 31. Both funds also have similar large-cap weightings, between 70-75%. However, MOO has only 35% of its holdings in U.S. stocks, while PAGG has more than 56% of its holdings in U.S. stocks, as of August 31.

And outside the U.S., Singapore (9.4%) is MOO's largest country weight, whereas PAGG has Canada as its second-largest country weighting (15.2%).

The PowerShares Global Gold and Precious Metals Portfolio (NasdaqGM: PSAU) and GDX shared seven out the top 10 holdings, as of Sept. 19. PSAU is more than 70% large-cap stocks, while GDX is only 50% large-caps and 36% mid-caps.

While Canada is both portfolios' largest country weight, GDX has a much higher weighting (63%) in it than does PSAU (41.3%). However, GDX has a much smaller weighting in South Africa, at 13.7%; PSAU has a 27.6% weighting in South Africa.

The PowerShares Global Coal Portfolio (NasdaqGM: PKOL) has virtually the same top holdings as KOL, with the exception of Cameco Corp., which is the fifth-largest holding in PKOL, but is not represented in KOL. PKOL's U.S. and Australia weights also present a slight differently profile. It has 40% in the U.S. and 16.5% in Australia, where KOL has 56% of its holdings in the U.S. and only 8% in Australian stocks. China is both funds' second-highest weight after the U.S., but KOL has Indonesia (8.9%) as its third-highest weight, rather than Australia.

In terms of cost, all the new PowerShares global hard assets funds' expense ratios are slightly higher than those of their Market Vectors competitors, at 0.75%. Market Vectors GDX and SLX charge 0.55%, while KOL and MOO charge 0.65%. 

Read the prospectus for the new PowerShares funds here.