The social media giant, which also owns Instagram and Whatsapp, is the 5th largest company in the U.S. based on the market cap of $973.1 billion. It is also the last company to have a market value below $1 trillion in the list. The company's stock has gained nearly 25% to date this year.Facebook, which was founded by Mark Zuckerberg in his dorm room in 2004, has achieved an astonishing growth in 17 years. With roughly 2.85 billion monthly active users as of the first quarter of 2021, Facebook is the biggest social network worldwide. The company, which generates almost all of its revenues primarily from advertising, has recently found itself under siege by American regulators and politicians, who want to keep the company under a tight rein.