In 2005 the most valuable company on Earth was ExxonMobil. An oil company at #1. If that sentence feels a little off to read now, that's exactly the point — it tells you what the last twenty years did.

A market cap ranking isn't just a rich list. It's a snapshot of what the world decided was worth money at that moment.

When Oil and Banks Ran the Table

Here's the 2005 global Top 10:

1. ExxonMobil (Oil) — $370B
2. GE (General Electric) — $350B
3. Microsoft — $280B
4. Citigroup (Finance) — $250B
5. BP (Oil) — $230B
6. Royal Dutch Shell (Oil) — $210B
7. Johnson & Johnson — $200B
8. Walmart — $190B
9. Bank of America — $180B
10. Toyota — $170B

Count them: three oil companies, two banks. The only thing you could call tech was Microsoft. Apple? Sitting at $18B, it didn't even crack the top 50 — which made sense, since the iPhone was still two years away.

2015: Tech Quietly Climbs the Top

A decade later, the upper rows look like a different planet:

1. Apple — $590B (33x its 2005 size)
2. Google (Alphabet) — $530B
3. Microsoft — $440B
4. ExxonMobil — $350B
5. Berkshire Hathaway — $330B

The whole top 3 is tech. One smartphone flipped the board. Meanwhile GE and Citigroup — once #2 and #4 — got hit by the financial crisis and rolled right out of the top 10.

Now AI and Chips Took the Whole Thing

Look at 2025. The first thing you notice: the unit jumped from billions to trillions.

1. Apple — $3.5T
2. NVIDIA — $3.3T (a company barely anyone knew in 2005)
3. Microsoft — $3.1T
4. Amazon — $2.3T
5. Alphabet (Google) — $2.1T
6. Meta (Facebook) — $1.6T
7. Tesla — $1.2T
8. TSMC — $1.0T
9. Broadcom — $0.9T
10. Berkshire Hathaway — $0.9T

Not a single oil company. Not a single bank. The two industries that filled half the 2005 list are gone, and tech, AI, and semiconductors ate every seat.

The Giants That Fell

Honestly, this is the part I find most interesting. The companies that climbed are fun, but the ones that fell teach you more.

GE. Once #2 in the world. The financial crisis plus a string of management failures erased over 90% of its market cap. By 2024 it had split into three separate companies.

Citigroup. The world's #4 bank. The subprime crisis crashed its stock 95%, and it needed a government bailout to survive.

PetroChina. It briefly hit $1 trillion in 2007, became the world's #1, then dropped like a stone. People still cite it as a textbook case of a market running too hot.

Here's where almost everyone gets fooled: "it's #1 now, so it'll stay #1." The moment the industry's current shifts, even giants just tip over.

The New Faces in Those Seats

NVIDIA. In 2005 it was a $6B GPU maker. Riding the AI boom, it became a $3.3T company — 550x in twenty years.

Tesla. $2B at its 2010 IPO. Now $1.2T. Practically a synonym for the word "EV."

TSMC. The dominant semiconductor foundry — the one selling picks and shovels in the AI gold rush.

So What About the Next Ten Years?

AI, quantum computing, biotech, space. The candidates to shake up the next board are already sprouting somewhere. A company that isn't even on today's top 10 could be sitting at #1 in 2035 — which is exactly what Apple did from 2005.

Want to test your gut for what companies are worth? Go try it head-to-head.