Differences noted for their impact upon search engine optimization included heavier keyword weighting and the importance of the domain's age.

Because of the way most stock indexes are constructed, funds that mimic them have heavier weightings in some sectors than in others.

The new-orders component, which carries the heaviest weighting, surged 6.3 points, to 64.2, its highest since July 1994.

"In a recession, banks tend to go down more than other stocks and our heavy financial weighting hurt us," Mr. Miller said.

It is the package's heavy weighting toward consumption taxes like the gasoline levy that causes it to hit the middle classes the hardest.

But it still gives heavy weighting to large-cap stocks.

Investors typically turn to balanced funds because their heavier weighting in bonds makes them a refuge from turmoil in stocks.

Many investors, of course, did not care about the heavy weighting in technology until recent weeks.

The Dow is normally calculated as a price-weighted index, meaning that stocks with the highest price for a share get the heaviest weighting.

Averages with a heavier weighting of secondary stocks generally have risen a more restrained 2 or 3 percent.