There is a steady and dramatic shift occurring in the investment world toward Exchange Traded Funds. ETFs as they are called, represent baskets of stocks which are managed only to match specific indexes, not to beat them, as is the case for actively managed mutual funds. According to a recent study by Barclays Global Investors US listed ETFs climbed to an all-time high of $607 billion at the end of August. The study suggests that a "conservative" growth rate of 20% compounded annually, would put ETFs above $1 trillion by mid-2011. That total would represent 10% of the US mutual fund industry. Brad Hintz, an analyst at Bernstein Research, in a Sept. 23rd research note said the growth of passive index products in general and ETFs in particular represent "a threat to traditional asset managers." He expects investors will focus even more on fees and tax efficiency with a sluggish outlook for stock and bond returns after the financial crisis. In this Brief I will demonstrate that there are even more significant advantages to the passive approach offered by ETFs than simply lower costs and taxes.