Why does the whole market follow the dow and nasdaq if each index is only made up of a few companies?

Question

do people see the dow and nasdaq indexes as a bellweather for panic or exhiliration? people seem to sell stocks frantically that are not a part of either index when they're going down and buy like crazy when they're going up. why?

Answer 1

you say a few like it is three or four companies but the reality if the bulk of companies being trades are represented on these exchanges.