In this installment of the My Roman Empire series, John and Brendan turn their obsession to the granddaddy of stock market benchmarks: the S&P 500.

Before diving in, the guys catch up after Brendan's New England vacation, debate whether pumpkin donuts have any business showing up before Labor Day, and brace for the inevitable early arrival of Christmas music.

In the main segment, John and Brendan trace the S&P 500's history — from its 1920s roots as a rival to the narrow Dow Jones index, through the 1957 rebrand, to John Bogle's 1976 breakthrough with the first index fund. They break down how companies get in (and get kicked out — RIP Enron and Blockbuster), what market-cap weighting actually means for your portfolio, and why today's top 10 holdings make up a historic 40% of the index amid the AI boom. They wrap up with why the S&P 500's rock-bottom fees make it a cornerstone for most portfolios.

Connect & Resources

• Website: oldirishguysfinancial.com
• Email: info@oldirishguysfinancial.com
• Catch up on the series: thepennythepint.transistor.fm

• (00:00) - – Intro & Banter: Vacation Wrap-Up, Back to School & Pumpkin Donut Chagrin
• (00:08) - – Getting In (and Kicked Out): Enron, WorldCom, Blockbuster & Kodak
• (00:11) - – My Roman Empire: What Is the S&P 500 & Why Was It Created?
• (00:18) - – Teaser: Today's Obsession — The S&P 500
• (00:21) - – Welcome Back & Housekeeping
• (00:21) - – Market-Cap Weighting & Concentration Risk Through History
• (00:31) - – John Bogle & the Birth of the Index Fund (1976)
• (00:34) - – The Alternative: Equal-Weighted S&P 500 Funds
• (00:45) - – Why It's a Cornerstone: Low Fees & Beating Managed Funds
• (00:52) - – Today's Top 10: The AI Boom & 40% Concentration
• (00:57) - – How It's Built: Market Cap Rules & the $61 Trillion Question