If you have trouble imagining a 20% loss in the stock market, you shouldn't be in stocks.

Ask yourself: Am I an investor, or am I a speculator? An investor is a person who owns business and holds it forever and enjoys the returns that U.S. businesses, and to some extent global businesses, have earned since the beginning of time. Speculation is betting on price. Speculation has no place in the portfolio or the kit of the typical investor.

The idea that a bell rings to signal when investors should get into or out of the stock market is simply not credible. After nearly fifty years in this business, I do not know of anybody who has done it successfully and consistently. I don't even know anybody who knows anybody who has done it successfully and consistently. Yet market timing appears to be increasingly embraced by mutual fund investors and the professional managers of fund portfolios alike.

It's very difficult for any particular segment of the stock market to sustain superior performance. The watch word for our financial markets is, "reversion to the mean" i.e. what goes up must come down, and it's true more often than you can imagine.

It's 1450 out of 1500 ETF funds that I just wouldn't touch because they're not diversified enough. Or they have some huge speculative twist to them that if you can guess the markets right you will do very well for a day or two but who can do that? Nobody.

Among my greatest disappointments about the mutual fund industry - in addition to excessive costs and excessive focus on the short-term - is that fund managers have been passive participants in corporate governance.

If the data do not prove that indexing wins, well, the data are wrong.