Exchange-traded funds are a broad class of funds, excluding closed-end funds, which trade throughout the day over an exchange. ETFs have low annual expenses, but you must pay commissions to trade them. ETFs do not redeem shares for cash, and thus do not need to sell securities (possibly realizing capital gains) to pay investors who redeem their shares. They are typically more tax-efficient than mutual funds. Unlike closed-end funds, ETFs market prices usually closely track their NAVs. Most ETFs are index funds. Here are some well-known types of ETFs:
DIAMONDs
Shares in an ETF, Diamonds Trust Series I, that track the Dow Jones Industrial Average. The fund is structured as a unit investment trust.
iShares
A group of ETFs advised and marketed by Barclays Global Investors. iShares are structured as open-end mutual funds.
HOLDRs
Holding company depository receipts, a type of ETF marketed by Merrill Lynch. Unlike other ETFs, HOLDRs can only be bought and sold in 100-share increments. HOLDRs do not have creation units like other ETFs, but investors may exchange 100 shares of a HOLDR for its underlying stocks at any time. Existing HOLDRs focus on narrow industry groups. Each initially owns 20 stocks, but they are unmanaged, and so can become more concentrated due to mergers, or the disparate performance of their holdings.
Qubes
The Nasdaq-100 tracking stock, an ETF that tracks the technology-laden Nasdaq-100 index. The popular name, Qubes, derives from the ETF's ticker symbol, QQQ. Qubes are structured as unit investment trusts. Qubes are by far the most heavily traded ETF.
Spiders (SPDRs)
SPDRs, or Standard & Poors' Depository Receipts. A group of ETFs that track a variety of Standard & Poors' indexes. SPDR Trust, Series 1, usually referred to as "Spiders," tracks the S&P 500 index. Select Sector SPDRs track various sector indices that carve up the S&P 500 index into separate industry groups. SPDR Trust, Series 1 is structured as a unit investment trust, but Select Sector SPDRs are open-end funds.
StreetTracks
A group of ETFs managed by State Street Global Advisors. These ETFs track various indexes, including Dow Jones style-specific and global indexes, technology indexes from Morgan Stanley Dean Witter, and the Wilshire REIT index. StreetTracks are open-end funds, not unit investment trusts, and trade on the American Stock Exchange.
Unit investment trust (UIT)
A structure used by some ETFs. One important difference between this format and the open-end fund format is that the latter allows ETFs to reinvest dividends immediately, while the former does not. This could result in ETFs that use the unit investment trust structure having a slight cash drag on their performance.
VIPERs (VIPRs)
Vanguard Index Participation Receipts: ETF versions of Vanguard index funds. VIPERs are structured as share classes of existing open-end funds.