An exchange-traded fund (or ETF) is an investment vehicle traded on stock
exchanges, The ETFs are traded much like stocks. Most ETFs track indexes and in
some cases they called "index tracking stocks". As an example QQQQ tracks the
Nasdaq 100 index, SPY tracks performance of the S&P 500 index, DIA track the Dow
Jones Industrial index, etc. An ETF holds assets such as stocks or bonds and
trades at approximately the same price as the net asset value of its underlying
assets over the course of the trading day. Because of their stock-like features,
low costs and tax efficiency the ETFs become attractive to many investors
and since their introduction they have fundamentally changed the way the
investors construct their investment portfolios.
An ETF combines the valuation feature of a mutual fund or unit investment trust
with the tradability feature of a closed-end fund. As a rule mutual funds can be
purchased or redeemed at the end of each trading day and close end funds can be
traded throughout the trading day. ETFs have been traded in the US since 1993
and in Europe they have been traded since 1999. Traditionally the Exchange
Traded Funds have been contracted as index funds, however, in 2008 the
United States Securities and Exchange Commission started to authorize the
creation of actively-managed ETFs.
From the moment ETFs was introduced they offer public investors ability to
invest into a pool of securities and other assets in similar to traditional
mutual funds way, with exception that ETFs shares can be traded (bought and
sold) throughout the day like stocks and they can be sold short like
stocks on a stock exchange.
Naked options trading is very risky - many people lose money trading them. It is recommended contacting your broker or investment professional to find out about trading risk and margin requirements before getting involved into trading uncovered options.