Stock Markets Exposed

Can you trade with the nasdaq,dow index on the stock market or only with companies listed on a nasdaq exchange?

If yes how are these points in the indexes calculated into profits.

Public Comments

1. You can invest in the indexes or with the individual companies listed in the NASDAQ or Dow. There is no difference as to how the profit/loss is calculated. If the index goes up over what you paid, the profit is based on how much.
2. You can buy Exchange Traded Funds which track the Dow (DIA) or NASDAQ (QQQQ) or the S&P 500 (SPY) as will as many other industry specific inicies. The ETFs trade like company shares.