The S&P 500 Visualized as a Treemap

What’s the best way to visualize the relative size of 505 stocks with respect to each other?

By size, we’re referring to the market capitalization of a company’s stock, which is the product of its price per share and the number of shares it has issued. And by 505 stocks, we’re referring to the stocks of the companies that make up the S&P 500 (Index: SPX).

Since the contribution of each of its component stocks are weighted according to their market cap, being able to visualize how its component firms compare to each other provides valuable information for investors. If you’re paying attention to the value of the index, you can use the information to quickly determine which individual stocks can most affect the index as their stock prices change.

Previously, we were impressed by how Visual Capitalist visualized the S&P 500, but now, we’ve come across another visualization that follows a similar approach, but delivers more interactive and timely information for investors/information consumers. Finviz, a financial information site that visualizes the relative size of the component firms that make up the S&P 500 index using a treemap chart.

Like the bubble chart-style presentation Visual Capitalist used, Finviz’ treemap of the S&P 500 groups firms from the same industrial sectors together. What takes Finviz’ presentation to the next level however is their chart is updated daily, indicating how much each component company’s market cap changed from the previous trading day. We took a snapshot of Finviz’ S&P 500 treemap after the end of trading on Friday, 4 August 2023, the day after the 2023-Q2 earnings announcements for Apple (NASDAQ: AAPL and Amazon (NASDAQ: AMZN. As you can quickly see from the snapshot, it was a bad day for Apple and the S&P 500 index overall, but a very good day for the smaller market cap Amazon.

Finviz’ treemap presentation is also interactive. You can zoom in on the S&P 500 treemap chart at their site to focus on smaller firms within a particular industrial sector. Meanwhile, clicking on a sector of the treemap will open a popup window presenting sparkline charts of each sector component firms’ stock prices over the past three months, so you can quickly get both its current share price and see how each share price has been trending.

All-in-all, we think Finviz’ approach for visualizing and presenting this data is very well done.