As a sample, last quarter Microsoft reported revenue of a bit over $9 billion. If they did that for the whole quarter, their total revenue might be $36 billion. Against a US GDP of 10 trillion. That isn't even a fraction of a percent of the US economy.

Of course Microsoft is more notable for profits than revenue. Let's go with a bigger company. You don't get bigger than General Electric, with the largest market cap in the world. They have also been around for a long time - they are the only member of the original DOW to still be listed in the DOW. How has their quest for world domination gone?

2004 was a good year for them. Their revenues were $152.2 billion, up from $134.2 billion the year before. That's under 2% of our GNP. But they are a worldwide company - I don't know what fraction of that income was US based. However even so, if after a century the most successful capitalist company in history can't manage to get to 2% of our GNP, then the dreaded future of a single monopoly that owns everything is going to be a looong way off.

Cheers,
Ben