Metals Go Mainstream

Base metals, says Newton, are in a corrective phase, so it's not the best time to have a long position there; however, he says, there likely still will be investors who want to be long.

While many expect the products will generate demand, others have yet to make up their mind.

"For the last year, commodities have been the hot market," says Dave Fry, founder and publisher of investment newsletter ETF Digest. But he points out that the recent volatility afflicting some commodities, such as copper and oil, makes it difficult to decide whether to invest in a commodity ETF right now.

More ETFs likely will come in the form of both single commodities and mixed baskets, as sponsors look to take advantage of the increasing interest in commodities and the growth of ETFs overall.