Dueling Market Caps: Apple and Microsoft

Apple is slowly but surely closing in on Microsoft in market cap.

According to Standard & Poor’s analyst Howard Silverblatt, Apple’s float-adjusted market capitalization reached $241.5 billion Thursday, edging past Microsoft’s $239.5 billion.

Said Silverblatt: “It came right down to the trade, but AAPL has an index market value of $241,534 million and MSFT has a market value of $239,515 million–AAPL is #2.”

Which means Apple (AAPL) is now second only to oil giant Exxon Mobil (XOM) on the S&P–on the index’s float-adjusted basis.

But on a full-market value basis–which, as Dan Frommer explains over at Business Insider, includes “shares that are closely held by control groups, other publicly traded companies or government agencies”–Microsoft (MSFT) remains firmly in second place, with a market cap of $275 billion–significantly larger than Apple’s.

So this float-adjusted achievement of Apple’s is really more of a psychological milestone than anything, one made possible only because S&P is counting just the 87 percent of Microsoft’s shares that are available for public trading. Below, a chart from Silicon Alley Insider that shows more clearly what’s happening.