There are two kinds of investors, be they large or small: those who don't know where the market is headed and those who don't know what they don't know. Then again, there is a third type of investor: the investment professional, who indeed knows he doesn't know, but whose livelihood depends upon appearing to know.

The key aspect of an index fund is that many of them, not all of them, but many of them are extremely cheap.

Market risk is like taking a plunge into a cool pool ... a lot of people are finding out right now what their risk tolerance is.

The key thing about any fund is to make sure its expenses are low. You know, if you look at the funds in your plan and you see that they're all charging 1.5 and 2 percent,you've gota bad plan.

While it is probably a poor idea to own actively managed funds in general, it is truly a terrible idea to own them in taxable accounts... taxes are a drag on performance of up to 4 percentage points each year... many index funds allow your capital gains to grow largely undisturbed until you sell... For the taxable investor, indexing means never having to say you're sorry.

When it comes to fund managers and market strategists, this year's hero usually turns into next year's zero.

It's human nature to find patterns where there are none and to find skill where luck is a more likely explanation (particularly if you're the lucky manager).