The "NASDAQ 100 Index" is an index that tracks the 100 largest stocks listed by the Nasdaq Composite Index. The Nasdaq 100 Index is often viewed as a barometer of technology stocks because the components in the Index are made up of mainly technology companies. Investors can bet on the direction of the Nasdaq 100 Index through the purchase of exchange traded funds (ETFs) that track the performance of the Nasdaq 100 Index.