Electronically Traded Funds or ETF's are similar to mutual funds but have some key advantages. They are traded on the stock market with a ticker symbol thus they can be sold at any time. Because of this however these can trade at a slight discount or premium to the NAV (Net asset value). ETF's can be bought in any quantity and because they are purchased and sold on the stock market fees associated with these items are a lot lower than normally traded mutual funds. Because they are traded on the open market there is often tax advantages associated with these items in that unlike mutual fund companies if a person redeems there shares the holding assets need not be sold which may create capital gains issues as those associated with mutual fund shares.