ETF Trends Editor Tom Lydon appeared on Yahoo Finance Breakout Tuesday to discuss the 20-year anniversary of the listing of SPDR S&P 500 ETF (NYSEArca: SPY), an event that changed the investing landscape forever.

The $127 billion fund was the first ETF listed in the U.S. and has blossomed into the most traded equity security on the planet. [SPY ‘Changed the Way Stocks Trade’]

“This little group — little think tank — at State Street said, ‘Let’s create this thing that might help trading the S&P 500,'” Lydon tells Breakout.

ETFs took a long time to catch on, “years and years and years,” Lydon adds. Today investors not only know what ETFs are, but they are using them to the point where Lydon says they’re “threatening mutual funds to a great degree.”

Watch the Breakout video to see the full interview.

Full disclosure: Tom Lydon’s clients own SPY.

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