Dow Jones Industrial Average
The oldest US index: a narrow set of large companies weighted by share price rather than by capitalisation.
How to read the number
Price weighting is a rarity today — a company with an optically expensive share moves the index more than a larger company with a cheap one.
When the metric lies
Its narrow membership and weighting method make it drift from the broad market more than capitalisation indices do; as a gauge of the economy it lost that argument long ago.
Also known as: djia