by , 8:10 AM EDT, April 14th, 2008

In a somewhat interesting development, at least in a macro-economic kind of way, Apple Inc. is now worth more than Citigroup, though it could be argued that technically, Citigroup is now worth less than Apple, as it is Citigroup's stock losses that has brought about most of the the relative shift in the two company's financial value.

Citigroup was the fourth-largest company in Standard & Poor's 500 Index of the largest corporations at the end of 2006. At that time, according to Tehran Times, which first noticed the shift, Citigroup's value was more than four times that of Apple.

Citigroup's stock has been severely punished by the markets as part of the broader mortgage crisis in the United States. At the close of the regular trading session on Friday, April 11th, Citigroup's market capitalization was $116.7 billion, while Apple closed with a market capitalization of $129.3 billion, a difference of $12.6 billion in Apple's favor.

Market capitalization (often referred to as "market cap") is a product of a company's stock price times the number of shares outstanding.

Part of what makes this valuation noteworthy is that Citigroup is a financial empire with assets and operations in a myriad of forms, and the company operates in many different markets, with many subsidiaries under its control. As of December 31, 2007, Citigroup's assets were reported at more than $2.18 trillion, while Apple's was a mere $25.3 billion.

That comparison isn't entirely black and white, though, as Citigroup's liabilities were listed at that same time at $2.07 trillion, while Apple's liabilities clocked in at some $10.8 billion. The simple math still leave us, however, with Citigroup being the far, far larger company in terms of assets.

Ultimately, however, a company's market cap is determined by the markets with a variety of factors that go far beyond anything as simple as a basic profit and loss statement, and that is what's at play when looking at these two companies.

"The market looks at what Steve Jobs has done and what he's likely to do," Michael Holland, who oversees more than $4 billion as chairman of Holland & Co. in New York, told Tehran Times. "The market is valuing that far more than the financial assets of Citigroup."

For longtime Mac users and AAPL stock observers, this shift is an excellent poster child for the ways in which the perception of Apple in the financial markets has undergone a radical transformation since the introduction of the iPod in late 2001.

Once derided as "beleaguered," and often the subject of imminent predictions of bankruptcy, sale, and other forms of corporate death, Apple is now a darling on Wall Street, and is playing in the rarified playground of the world's largest corporations.

*In the interest of full disclosure, the author holds a small share in AAPL stock that was not an influence in the creation of this article.