Stock market is a market place to trade shares. SEBI regulates the stock market and it brings in transparency of stock trade. NSE & BSE are two main markets where NSE is newer market with >1500 companies, technology and liquidity. shares are public listed through IPO as primary market and then it is traded as secondary market. SENSEX is bse top thirty traded companies & Nifty is NSE top fifty traded companies. Index for a sample understanding of market performance. Demat is dematerialised format of physical share certificate.