Dow Jones Industrial Average
Also called: the Dow, DJIA, Dow Jones
The Dow Jones Industrial Average tracks 30 large US companies and is the oldest widely quoted index — and the most methodologically odd. It is price-weighted, meaning a $500 stock influences it ten times as much as a $50 stock regardless of company size, an artefact of being designed in 1896 for hand calculation. It remains the headline number in general news and the least useful of the major indexes for actual analysis.