The Dow Jones Industrial Average announced a major shakeup on Monday after the market closed — it booted Pfizer, Raytheon Technologies and ExxonMobil, the oldest member of the index, having joined in 1928.

What happened: Salesforce, Amgen and Honeywell will replace those companies to "help diversify the index ... and adding new types of businesses that better reflect the American economy," S&P Dow Jones Indices said in a note announcing the changes.

• The new companies join the Dow on Aug. 31.
• GE, the last original member of the Dow, was removed two years ago

Driving the news: The changes seem more reflective of a desire for better-performing stocks than more accurate representation of a changing U.S. economy — the Dow will actually have a lower percentage of tech after the additions.

• Because the Dow is a stock-price-weighed index, Apple's four-to-one stock split would have reduced the Dow's weighting of tech stocks from 27.6% to 20.3%.
• “By adding Salesforce, you can come back to 23.1% of the Dow being in technology,” Howard Silverblatt, senior index analyst at S&P Dow Jones Indices, told CNBC.

Reality check: The Dow was designed to measure the strength of the U.S. stock market and economy, but in recent years it has been left in the dust by the tech-heavy Nasdaq.

By the numbers: Over the last five years, the Nasdaq has produced almost double the Dow's gain (151% vs. 78%) and over the last year it has returned nearly five times what the Dow has (47% vs. 10%), per FactSet.

• Year to date, the Nasdaq has risen just under 27% while the Dow remains underwater for 2020.
• The Nasdaq 100, which includes the 100 largest non-finance stocks in the index, is up 33% this year.

Between the lines: Despite recently becoming a net oil exporter, U.S. oil companies' stocks have fared poorly and indexes excluding energy and oil names have tended to outperform those that do include them.

• Energy companies made up as much as a quarter of the Dow in the 1980s, and Exxon remained the most valuable company in the U.S. through much of the early 2000s and as recently as 2011, when it hit a market value of just over $400 billion.
• Apple overtook Exxon in 2012, and today has a market cap over $2 trillion while Exxon's market cap has sunk to $175 billion.
• With Exxon's exit on Monday, energy will account for just 2% of the Dow.

The bottom line: Roughly $31.5 billion of assets are benchmarked to the Dow, and $28.2 billion of passively managed funds, compared to $11.2 trillion and $4.6 trillion for the S&P 500, according to Bloomberg.