Today saw the launch of two new members of the WisdomTree Dreyfus Currency Income exchange-traded funds family, bringing the total number of ETFs in the series to seven.

The WisdomTree Dreyfus South African Rand Fund (NYSE: SZR) and the WisdomTree Dreyfus New Zealand Dollar Fund (NYSE: BNZ) both charge expense ratios of 0.45%. They join other WisdomTree Dreyfus funds covering the Chinese yuan, the Indian rupee, the Brazilian real, the euro and the Japanese yen.

WisdomTree teamed up with The Dreyfus Corporation to create the funds, which are designed to earn income that reflects the money market rates of their respective currencies but are not traditional money market funds. The ETFs invest primarily in short-term, investment-grade debt and seek to maintain an average portfolio maturity of 60 days.

According to Bruce Lavine, WisdomTree's president and COO, the existing ETFs in the WisdomTree Dreyfus family have already taken in a total of $350 million in assets since their launch in mid-May. He also noted that the New Zealand dollar and South African rand are among the highest yielding currencies of the developed and developing markets, respectively.

WisdomTree also has the WisdomTree U.S. Current Income Fund (NYSE: USY), which invests in domestic money market securities but does not fall under the WisdomTree Dreyfus co-branding deal.

Read the prospectus for the new funds here.