How Big was IBM?

Today, Nvidia grabs the headlines as the most valuable company in the world, with a market value of over $4 trillion. Over the last few years tech giants Alphabet, Apple and Microsoft have each also vied with each other for that title. Today each of these firms has a market value of more than $3 trillion.

If we go back in time far enough though, one firm stood alone as the most valuable technology company in the world. It held this crown for many years. Its dominance was built on its position as the leading supplier of both hardware and software to a majority of the leading companies in the US and more widely. That company was, of course, International Business Machines also known as IBM or ‘Big Blue’.

In fact IBM wasn’t just the most valuable tech company it was, for a while, the most valuable company in the world.

IBM today is a shadow of its former self. Its dominance long gone, it has defended its, highly profitable, place as a supplier of legacy mainframe systems and software, but other than that the business today is seemingly mostly focused on selling consulting services.

In reality, today’s, apparently much diminished, IBM is still a big company: it’s just behind AMD with a market value of around $230 billion.

This begs some questions. If it was so dominant, then how big was IBM at it’s peak? How does that peak compare with today’s tech giants? In the rest of this post we’ll try to answer these questions and to put IBM’s size and dominance into context.

So how big was IBM?

Even at its peak IBM’s market value, adjusted for inflation, never reached the heights of today’s biggest tech firms. In 1985 IBM had a market value of around $90 billion (around $270 billion adjusted for inflation in 2025 dollars1) ahead of Exxon and General Motors in the number two and three spots. 1985 is perhaps one of the last years when IBM was generally seen as being preeminent.

Note that a simple web search for IBM’s market value gives the wrong answer. For example this article from Motley Fool hosted on the Nasdaq website quotes a value of ‘around $30 billion’. This is wrong. Coming up with the actual market value is more complex than might be expected and the reason why this estimate and others are