“What would I do? I’d shut it down and give the money back to the shareholders.” (link)

The irony, as we noted last October, was that Apple’s (AAPL) market cap was then double that of Dell, Inc. (DELL). Since then, Apple’s value has gone on to triple and, last week, quadruple Dell’s. Here, thanks to
MacDailyNews
, are the market cap milestones:

• Jan. 13, 2006 Apple passes Dell: $72.13 billion vs. $71.97 billion
• July 27, 2007 Apple doubles Dell: $127.81 billion vs. $63.65 billion
• Dec. 6, 2007 Apple triples Dell: $165.66 billion vs. $54.42 billion
• May 1, 2008 Apple quadruples Dell: $158.66 billion vs. $38.97 billion

By week’s end, Apple was worth 4.04 Dells.

Michael Dell, however, is still worth 3.01 Steve Jobs, according to the latest list of the richest Americans:

• Dell’s net worth: $17.2 billion
• Jobs’ net worth: $5.7 billion

And according to IDC, Dell is America’s No. 1 PC maker, with a 30.9% U.S. market share, while Apple is No. 4 with 6%.

So why the big difference in market capitalization? Apple’s track record of innovation, integration and customer service has something to do with it, but investors pay even more attention to the margins.

• Apple Profit margin: 15.13% Operating margin: 19.28%
• Dell Profit margin: 4.82% Operating margin: 5.91% [Source: Yahoo Finance]

In other words, Dell sells a lot more machines, but Apple makes way more profit on each machine it sells.