A new group of exhange-traded notes is designed to improve on an initial attempt to track commodity guru Jim Rogers’s international commodity indexes. After a two-week delay because of Hurricane Sandy, the five new “enhanced” ETNs based on Rogers’ RICI indexes opened for trading on the New York Stock Exchange’s NYSE Arca platform earlier this month.

Sponsored by the Royal Bank of Scotland (RBS), the group includes one broad-based, multicommodity ETN (RGRC), and four ETNs on specific segments: agriculture (RGRA); energy (RGRE); precious metals (RGRP); and industrial metals (RGRI). Each will be launched with $4 million in seed capital, says Tom Haines, RBS’s head of Northern American indexes and listed products, based in Stamford, Connecticut.

They’re not the first ETNs based on the RICI indexes to hit the U.S. market. Back in October 2007 Merrill Lynch, now a subsidiary of Bank of America, launched four ETNs based on Rogers’s indexes as part of its “Elements” series. Those ETNs, issued by the Swedish Export Credit Corporation (SEK), include one ETN for all of the metals (RJZ), which had $37.3 million in assets as of November 12. Other than that, it’s the same line-up, with a multicommodity ETN (RJI) with $625.7 million in assets; an agriculture ETN (RJA) with $381 million; and an energy ETN (RJN) with $67.8 million.

The returns on the original ETNs have been less than impressive, according to Merrill’s public documents. The RJI broad-based ETN has a five-year gain of 4.09 percent and a year-to-date loss of 0.47 percent as of November 12. The biggest gainer was the RJA agriculture ETN with a five-year gain of 6.35 percent and a year-to-date gain of 2.57 percent; the biggest loser was the RJN energy ETN with a five-year gain of just 0.43 percent and a year-to-date loss of 8.70 percent; and the RJZ metals ETN had a five-year gain of 4.60 percent and a year-to-date gain of 2.22 percent.

So why should anyone get excited about another series of ETNs based on Jim Rogers’s indexes? Because RBS believes that they’ve come up with a series that can do better.

The original RICI index that Merrill’s ETNs follow is structured so that Merrill is required to consistently reinvest in front-month futures contracts.