

Buffett points out that the Dow's annual compounded gain was 5.3 percent in the 20th century .. and it was a "wonderful" century. To match that rate in the 21st century, the Dow would need to close around 2,000,000 at the end of 2099. (1,988,000 Dow points to go, eight years in.)

Anyone expecting a 10 percent annual gains from stocks this century are "implicitly forecasting a level of about 24,000,000 on the Dow by 2100." (Buffett suggests you explain the math to any adviser who talks to you about double-digit gains, "not that it will faze him.") He warns, "Beware the glib helper who fills your head with fantasies while he fills his pockets with fees."

That doesn't mean you shouldn't put money into stocks. I think it means you shouldn't pay someone to manage your stock investments, just because that person says he or she can get you fantastic returns that beat the overall market. In the past, Buffett has recommended stock index mutual funds for many 'regular' investors.

The discussion gives context to the question Buffett asked us to ask youabout where the Dow will be in 2099. He'll be talking more about that Monday morning when he joins Becky Quick live in Omaha on CNBC's Squawk Box starting at 6am ET. I'll also provide "live blog" coverage of the whole thing here on Warren Buffett Watch.

Buffett and Becky will chat several times during Squawk's three hours. For the first time ever, Buffett will be answering some of your questions, submitted to us by email. (Thank you to everyone who has already sent in questions or will be doing so. We're only sorry Buffett won't be able to answer them all!)

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