What Is a Stock Market Index? BIST 100, S&P 500 and Others

A stock market index measures the performance of a group of stocks.

Major Global Indices:
- S&P 500 (USA): Largest 500 American companies
- Dow Jones (USA): 30 major industrial companies
- Nasdaq 100 (USA): 100 technology-heavy companies
- FTSE 100 (UK): 100 companies on the London Stock Exchange
- DAX 40 (Germany): 40 companies on the Frankfurt Stock Exchange
- Nikkei 225 (Japan): 225 companies on the Tokyo Stock Exchange
- BIST 100 (Turkey): 100 companies on Borsa Istanbul

Investing in Indices:
Instead of picking individual stocks, invest in overall market performance through index funds and ETFs. This offers instant diversification and typically lower fees.