During the fourth quarter, expense ratios in most ETF categories increased modestly or remained the same from the third quarter.
The "industry and sector" group had 169 funds, making it the largest ETF category. The expense ratio median of this group stayed level at 0.50 percent, even though 10 Vanguard sector ETFs had their annual expense ratios reduced to 0.22 percent.
The number of bond ETFs began 2007 at 14 and has since risen to 44 funds. Municipal bond ETFs from Barclays, PowerShares and State Street Global Advisors were added during the third and fourth quarter. The median expense ratio for all bond ETFs stayed level at 0.20 percent.
Rydex CurrencyShares dominates the field when it comes to currency offerings, the smallest ETF category. As of mid-quarter, there were eight CurrencyShares products tracking a broad spectrum of single currencies, including the euro, pound sterling, Canadian dollar and Mexican peso. The median expense ratio for all currency ETFs was 0.40 percent.
Ron DeLegge is the San Diego-based editor of www.etfguide.com.