Global X is the next company to join the rush into metals ETFs with the registration of four funds tracking companies linked to copper, gold, platinum and silver mining.

While many other companies like PowerShares, iShares and UBS offer plays on precious metals through investments in derivatives contracts, Van Eck and ALPS are among the names taking the equities route for a commodities strategy.

In particular, Van Eck's metals ETFs—the Market Vectors Gold Miners ETF (NYSEArca: GDX) and Junior Gold Miners ETF (NYSEArca: GDXJ)—have been hugely successful at attracting assets and have paved the way for others to follow.

And following they are. Just last week First Trust filed paperwork to launch its own take on equities-linked platinum and copper ETFs through two funds designed to provide investors not only with a broad play on those markets but also with exposure to smaller, more pure-play companies by allowing them to have an added weight in the portfolios.

It's worth noting that equity-based commodities products aren’t a one-for-one replacement for futures or spot price exposure, because equities are necessarily impacted by trends in the broader stock market. While the long-term correlation between equities and futures is good, it's also not perfect, and investing in commodities-linked equities can be more volatile than tracking spot prices of commodities.

The Global X funds are:

• Global X Copper Miners ETF
• Global X Gold Miners ETF
• Global X Platinum Miners ETF
• Global X Silver Miners ETF

Tracking respective market-cap-weighted, free-float-adjusted Solactive Global indexes provided by Structured Solutions AG, each ETF will essentially be a broad-based play in each of those markets. By investing in mining companies rather than in the physical metals themselves, the ETFs could over- or under-perform the actual price movements of the metals in the short and long term.

They will employ a fully replicating strategy and invest in securities as well as various depositary receipts.

Global X Management Company is the adviser for the funds, which should be listed on the NYSE Arca.

You can read the prospectus here.