Tech companies often have different fiscal years and announce their quarterly result on different days, so it's hard to make comparisons, even if you have a superhuman memory.
However, a simple bar chart makes the obvious point: the old order has changed. IBM no longer dwarfs every other IT company. That function has been taken over by Apple. Its profits (below) give Apple an even more dramatic lead: it made more in its last quarter than IBM makes in a year. Its most notable challenger is Samsung, but that's a conglomerate, and it's hard to figure out how comparable Samsung Electronics really is.
Hewlett-Packard is another company that could once be described as "the world's largest IT supplier" after it absorbed Compaq, DEC (Digital Equipment Corp) and other rivals. Today, it looks as though it will be overtaken by Microsoft, though given HP's plans to split itself into two companies, this doesn't really matter.
As I noted in a previous post, Microsoft has just overtaken IBM for the first time, in quarterly if not annual revenues. Both are in the process of transforming themselves for a mobile first/cloud first world, and especially for the "hybrid cloud" that currently looks the best bet for large corporations.
It remains to be seen which of them will be more successful. On previous form, you'd have to go with Microsoft. And if it comes down to confidence in management, it would be hard to pick IBM's Ginni Rometty over Microsoft's Satya Nadella.
When it comes to the challengers, both Google and Lenovo are showing promise, though Google's profitability is obviously in a different league, thanks to its web search monopoly. A lot of Lenovo's revenues come from low-margin Windows and Android hardware - including its PC and x86 server businesses, which used to be part of IBM.
A different chart of web-based companies would show Google towering over Facebook, Yahoo and their ilk, but we don't know if, or when, it will emulate Microsoft in overtaking IBM. Like IBM, Google is a voracious devourer of smaller companies, but it is making much bigger bets. It's putting search profits into moonshot projects such as Google Glass, home monitoring (Nest), robots and self-driving cars. The returns are minuscule at the moment, but the pay-offs could be enormous.
Google's problem is that it doesn't have an infinite amount of time. It has grown with the web - a rising tide lifts all boats - but there will eventually be a conflict between the rising cost of moonshots and the declining cost of a search ad. That day will arrive even quicker if upstarts like Facebook, Twitter, Snapchat, and Facebook's Instagram and WhatsApp, ever figure out how to make real money from all their traffic.