Where the Hot ETF Action Is

(SHLD) Vanguard and WisdomTree are the destination for buy-and-hold investors, while Direxion captured the traders. Meanwhile, Van Eck's Market Vectors ETFs were among the fastest growing ETFs last month.

The fastest-growing ETPs, measured by growth in assets under management, were a mix of the most volatile emerging markets, leveraged ETFs and commodity ETNs. Risk was the trade of the month, and investors headed for these funds even if they lost money -- in four cases, all bear market funds, net inflows exceeded total asset growth.

Many of these funds were also among those seeing the fastest growth via inflows, a topic I covered last week. The ones seeing the most growth due to price appreciation were Market Vectors Indonesia(IDX), Market Vectors Brazil Small Cap(BRF), SDPR S&P International Technology(IPK), iPath Nickel ETN(JJN), iShares MSCI Peru(EPU) and Claymore/AlphaShares China Small Cap(HAO). As long as the market advances, these more volatile funds will attract more assets and outperform the market.

Among ETFs with more than $500 million in assets, those with the largest growth in AUM included iShares DJ U.S. Basic Materials(IYM), iShares DJ U.S. Real Estate(IYR), SPDR S&P Homebuilders(XHB), PowerShares VRDO Tax Free Weekly(PVI), iPath India ETN(INP) and iShares Hong Kong(EWH). The standout fund here is PVI.

PVI holds variable rate demand obligations (VRDOs), bonds that usually trade with minimum denominations of $100,000, meaning most investors are unfamiliar with them. One selling point that no doubt attracts income investors is the stability of PVI. Its NAV has moved only 0.5% from its all-time high to its all-time low -- in nearly two years of trading. This means an investor's principle is protected while he or she collects monthly dividends, which currently amount to about 1.3% on an annualized basis. However, the variable rates adjust weekly, so this fund's yield will increase if rates move higher.