The software giant broke the barrier on Wednesday in after-hours trading when shares jumped more than 4% on better-than-expected earnings and revenue.
The boost makes Microsoft the third company to hit that market-cap mark, as well as the most valuable US company, based on the trading price of all of a company's shares added together.
Apple and Amazon were the first companies to hit the mark last year, but their current market caps are now under 1 trillion USD.
