[crystaldev]

Yes, and also some companies may be affected more by their own fortunes, or the fortunes of their particular industry, than by the mood of a monolithic "market."

[Scarblac]

But it seems to be accepted wisdom nowadays that nobody can pick stocks and beat the average consistently.

So what a large chunk of the market ends up doing is buying index trackers or achieving the same goal by spreading investments as widely as possible.

[perl4ever]

The nice thing about indexes is there are so many of them...

I read somewhere there are actually more ETFs now than individual stocks.