How realistic is this expectation (earn 9.2% from equity investment)? Let’s revisit some data I mentioned two years ago: During the 20th Century, the Dow advanced from 66 to 11,497. This gain, though it appears huge, shrinks to 5.3% when compounded annually. An investor who owned the Dow throughout the century would also have received generous dividends for much of the period, but only about 2% or so in the final years. It was a wonderful century.

Think now about this century. For investors to merely match that 5.3% market-value gain, the Dow – recently below 13,000 – would need to close at about 2,000,000 on December 31, 2099. We are now eight years into this century, and we have racked up less than 2,000 of the 1,988,000 Dow points the market needed to travel in this hundred years to equal the 5.3% of the last.

It’s amusing that commentators regularly hyperventilate at the prospect of the Dow crossing an even number of thousands, such as 14,000 or 15,000. If they keep reacting that way, a 5.3% annual gain for the century will mean they experience at least 1,986 seizures during the next 92 years. While anything is possible, does anyone really believe this is the most likely outcome?

…

I should mention that people who expect to earn 10% annually from equities during this century – envisioning that 2% of that will come from dividends and 8% from price appreciation – are implicitly forecasting a level of about 2,000,000 on the Dow by 2100. If your adviser talks to you about double digit returns from equities, explain this math to him – not that it will faze him. Many helpers are apparently direct descendants of the queen in Alice in Wonderland, who said: “Why, sometimes I’ve believed as many as six impossible things before breakfast.” Beware the glib helper who fills your head with fantasies while he fills his pockets with fees.

Warren Buffet, Feb. 2008.