Investors piled into riskier exchange traded funds during October’s rally, with ETFs tracking emerging markets and U.S. high-yield corporate bonds among the inflow leaders.

The iShares MSCI Emerging Markets (NYSEArca: EEM) was the top-selling U.S.-listed ETF in October, according to data from National Stock Exchange. It hauled in $3.7 billion in net cash inflows last month. However, the emerging markets ETF has experienced outflows of $7.1 billion year to date. [October ETF Performance Report]

Meanwhile, the small-cap iShares Russell (NYSEArca: IWM) saw $2.9 billion move in the door. The other best-selling ETFs in October were PowerShares QQQ (NasdaqGM: QQQ), SPDR Dow Jones Industrial Average (NYSEArca: DIA) and Vanguard Emerging Markets (NYSEArca: VWO). [ETF Chart of the Day: Emerging Markets]

Investors also shoveled money into “junk” bonds as iShares iBoxx High Yield Corporate Bond (NYSEArca: HYG) and SPDR Barclays Capital High Yield Bond (NYSEArca: JNK) posted inflows of about $1 billion each. [High-Yield Bond ETF Rally]

Elsewhere in corporate bonds, iShares iBoxx Investment Grade Corporate Bond (NYSEArca: LQD) added $868 million in fresh assets in October, according to NSX. [Strategist Likes Corporate Bond ETFs]

Bargain hunters also seemed to be present in the beaten-down financial sector – Financial Select Sector SPDR (NYSEArca: XLF) saw net inflows of $848 million last month. [ETFs See $24 Billion October Inflow]

The year-to-date figures show that dividend ETFs have been a popular theme in 2011 as investors look outside the traditional areas to add yield to portfolios. Vanguard Dividend Appreciation (NYSEArca: VIG) has posted cash inflows of $3.4 billion so far this year, while SPDR S&P Dividend (NYSEArca: SDY) and iShares Dow Jones U.S. Select Dividend (NYSEArca: DVY) have each added $2.1 billion. [4 Dividend ETFs]