ETFs are different from Mutual funds in the sense that ETF units are not sold to the public for cash. Instead, the Asset Management Company that sponsors the ETF (Fund) takes the shares of companies comprising the index from various categories of investors like authorized participants, large investors and institutions. In turn, it issues them a large block of ETF units. Since dividend may have accumulated for the stocks at any point in time, a cash component to that extent is also taken from such investors. In other words, a large block of ETF units called a "Creation Unit" is exchanged for a "Portfolio Deposit" of stocks and "Cash Component".

The number of outstanding ETF units is not limited, as with traditional mutual funds. It may increase if investors deposit shares to create ETF units; or it may reduce on a day if some ETF holders redeem their ETF units for the underlying shares. These transactions are conducted by sending creation / redemption instructions to the Fund. The Portfolio Deposit closely approximates the proportion of the stocks in the index together with a specified amount of Cash Component. This "in-kind" creation / redemption facility ensures that ETFs trade close to their fair value at any given time.

Some investors may prefer to hold the creation units in their portfolios. While others may break-up the creation units and sell on the exchanges, where individual investors may purchase them just like any other shares.

ETF units are continuously created and redeemed based on investor demand. Investors may use ETFs for investment, trading or arbitrage. The price of the ETF tracks the value of the underlying index. This provides an opportunity to investors to compare the value of underlying index against the price of the ETF units prevailing on the Exchange. If the value of the underlying index is higher than the price of the ETF, the investors may redeem the units to the Sponsor in exchange for the higher priced securities. Conversely, if the price of the underlying securities is lower than the ETF, the investors may create ETF units by depositing the lower-priced securities. This arbitrage mechanism eliminates the problem associated with closed-end mutual funds viz. the premium or discount to the NAV.