In August of 1997, Apple and Microsoft decided to put the past behind them and focus on the future. At that year's Macworld event, Steve Jobs and Bill Gates announced that the two companies had entered into a historic agreement. In addition to agreeing to a broad patent cross-licensing agreement, Microsoft promised to support Microsoft Office for the Mac for 5 years while Apple agreed to make Internet Explorer the default web browser on the Mac.

Microsoft also promised to invest approximately $150 million for shares of Apple non-voting preferred stock. Though the Mac faithful at the time were wary of Microsoft, Steve Jobs at the time famously explained that "we have to let go of this notion that for Apple to win, Microsoft has to lose."

The deal between the two companies was mutually beneficial from every angle. Apple got some much needed cash while Microsoft was able to keep a weakened competitor afloat, thereby alleviating concerns about the company's monopolistic power.

Since then, Apple has enjoyed an unparalleled resurgence, ascending from the brink of bankruptcy to one of the most valuable companies on the planet.

That being the case, one can only wonder: What ever became of Microsoft's $150 million investment?

Here's the scoop.

Microsoft's $150 million investment netted the company 150,000 shares of preferred stock, convertable to common shares of Apple stock at a price of $8.25, redeemable after a three year period. By 2001, Microsoft had converted all of its shares into common stock, netting the company approximately 18.1 million shares.

But by 2003, Microsoft had sold its entire stake in Apple.

But what if the folks at Redmond decided to hold on to their Apple shares? How much would they be worth today?

Well, Apple stock split on a 2-for-1 basis twice since the agreement, once in June of 2000 and again in 2005. At the time of the first split, the three year window had not yet passed so let's just assume that Microsoft's shares would have split only once. That would have given the company 36.2 million shares.

At the close of trading on Monday, shares of Apple were trading at $604.59. If Microsoft still had their shares, they'd be worth $21.86 billion, a hell of a return for the initial outlay of $150 million.

Note that this isn't meant to disparage Microsoft, but rather to point out how incredibly high Apple's share price has been. And besides, the influx of cash was never about Microsoft pursuing an investment opportunity.