Exchange Traded Fund (ETF) is getting popular among the investors, total global asset value has exceeded US$3 trillion.  ETF has the best DNA of both stocks and investment funds.  ETF is an investment fund which can be traded like stocks, having the stability of investment funds (risk diversification over a large portfolio) and flexibility of stocks (buy / sell in stock market) with minimal fund management fee. There are thousands of ETFs globally over various investment markets, eg:

• Stocks: SPY, STI, QQQ, RSX, XLE…
• Bonds: SHY, TIP, AGG…
• Commodities: USO, GLD, DBA…
• Currencies: FXA, FXB, FXC…

Famous ETFs providers are SPDRs, iShares, PowerShares, ProShares, Vanguard, etc.  For stocks ETFs, it could be related to stock indices, sectors or a group of stocks selected by the fund managers, either actively or passively managed.  Some ETFs could be operated inversely (shorting, eg, PSQ – ......