A lot can change in 15 years. Nowhere is this more true than on the stock market. For example, in just 15 years, the total annual revenue of the five largest American companies has soared 50% from $1.6 trillion to $2.4 trillion. That alone is a huge difference, but there's something even more dramatic behind the numbers: Only one of the companies that appeared in the 2009 list remains within the top five.

Let's dig in and see which stocks have shouldered their way into the top five and which have dropped out.

The five largest companies in 2009

First off, a few notes on methodology. This list is made up of American-based public companies. Also, I'm using annual revenue as my measuring stick rather than a valuation metric, such as market capitalization. With that in mind, let's have a look at the list:

Company Name Symbol 2009 Revenue (in billions)
ExxonMobil XOM $466
Walmart WMT $404
Chevron CVX $268
ConocoPhillips COP $241
General Electric GE $182

Data source: YCharts.

As you can see, in 2009, energy companies dominated the list of largest companies. ExxonMobil, Chevron, and ConocoPhillips held down three of the top four spots. Meanwhile, retail giant Walmart sat in second place, and industrial conglomerate General Electric rounded out the list in fifth. Notably, there were no technology companies in the top five.

The five largest companies in 2024

Fast forward 15 years, and things have changed a lot.

Company Name Symbol 2023 Revenue (in billions)
Walmart WMT $648
Amazon AAPL $575
Berkshire Hathaway BRK.B $439
Apple AAPL $383
UnitedHealth Group UNH $368

Data source: YCharts.

First off, there are no energy stocks on the list. ExxonMobil, Chevron, and ConocoPhillips have all disappeared. General Electric is gone too. However, one holdover remains -- Walmart -- and takes the top spot.

Two "Magnificent Seven" stocks are among those joining the list: Apple and Amazon.

Berkshire Hathaway also makes the cut thanks to its enormous investment portfolio (including a hefty portion of Apple stock). As does healthcare giant UnitedHealth.