NASDAQ is an acronym for National Association of Securities Dealers Antiquated Quotation system and is the largest U.S. electronic stock market.

The NDX represents 100 of the largest domestic and international non-financial securities listed on the NASDAQ. It is based on market capitalization both in its selection and weighting characteristics.

The Nasdaq Composite Index represents more than 3,000 companies traded on the National Market System which are smaller growth companies, many in technology and financial services.

The NMS began in 1978, as a result of the Securities Act Amendments of 1975, and linked nine markets electronically by ITS computers. They include American, Boston, Cincinnati, Chicago, New York, Pacific, Philadelphia and NASD OTC.

This data is often used as a reference for the breadth of a market move. New Highs refer to the number of stocks in a given market (NYSE, NASDAQ, AMEX) that are making new 52-week highs. New Lows refer to stocks making new 52-week lows. These data points are reported separately but also represented as a fraction of New Highs over New Lows for which a moving average can be given.