The SPDR S&P 500 ETF Trust (SPY Quick QuoteSPY - Free Report) , the largest ETF in the world, celebrated its 30^th birthday on Sunday.  The launch revolutionized the investment world, and the ETF industry has come a long way since then with over 3,000 US-listed ETFs and about $6.5 trillion in assets under management.

SPY is also the most actively traded equity security with average daily trading volumes of about $39 billion, more than three times as much as Apple’s stock, per FT. Due to its unparalleled liquidity, there is a large ecosystem of derivatives built on SPY.

The iShares Core S&P 500 ETF (IVV Quick QuoteIVV - Free Report) , the Vanguard S&P 500 ETF (VOO Quick QuoteVOO - Free Report) and the SPDR Portfolio S&P 500 ETF (SPLG Quick QuoteSPLG - Free Report) track the same index and charge just 0.03% in expense ratio compared to SPY’s 0.09%. Apple (AAPL Quick QuoteAAPL - Free Report) Microsoft (MSFT Quick QuoteMSFT - Free Report) Alphabet (GOOGL Quick QuoteGOOGL - Free Report) are the top holdings in these ETFs.

SPY has been losing market share at the asset level to the cheaper alternatives, but it remains very popular with traders and institutional investors.

To learn more, please watch the short video above.