The change is just the latest signal that the technology sector has shifted away from hardware and hard-copy software sales toward Internet ads and mobile technology.
At the close of markets on Monday, Google had a market value of $249.9billion, compared to $247.2billion for Microsoft.
Rising and falling: Google (red line) has
skyrocketed more than 30 percent in the last three months. Microsoft
(blue line), meanwhile, has stayed flat
Wire.com reports that Google's Wall Street coupe is a result of its impressive share of the mobile market.
Its Android operating system is installed on nearly two thirds of all smartphones sold across the globe.
The Windows mobile operating system has captured only 4 percent of the market, despite positive reviews by technology gurus.
Google has also led the way in the word of web-based software and computing.
Microsoft still relies heavily on its expensive software and operating system packages like Windows and Office.
Slow-moving: Microsoft, once the biggest public
company in the world, is now struggling to maintain its power in the
new tech industry
Speeding ahead: Google, meanwhile, has cornered the search, online advertising and mobile devices markets
Google projects it will pull in that same amount of money from its mobile division, alone.
That leaves aside Google's core business, which is online search and targeted ad sales.
Google's search engine, which is so commonplace in society that it has become a verb, makes up 66 percent of the world's search traffic.
Microsoft's Bing, the number two search engine, captures just 16 percent of traffic.
Google, whose stock price stands at $761.78 a share, rose one percent on Monday.
Markets have been bullish on Google in recent months. Share prices have risen 31 percent in the last three months.
Microsoft, meanwhile, has remained flat. Share fell one percent, to close at $29.49.
The company's stock value has fallen 3.6 percent since July.