The Nasdaq-100 is a stock market index that includes 100 of the largest non-financial companies listed on the Nasdaq Stock Market. It represents a diverse range of industries, including technology, consumer services, and healthcare. The index is often used as a benchmark for the performance of the technology sector. Investors and analysts closely monitor the Nasdaq-100 because it includes well-known companies like Apple, Amazon, and Microsoft. The index is weighted by market capitalization, meaning larger companies have a greater impact on its overall performance. This makes it a key indicator of trends in the stock market.