Tech is in. Oil is out.

Facebook overtook Exxon Mobil on Monday to become the fourth most valuable company in the world by market capitalization, pushing the oil and gas giant behind not one but four technology giant in the rankings.

The social network's market value surged by tens of billions of dollars in recent days after posting a flawless earnings report last week showing continued gains in users and advertising revenue on smartphones and tablets. That same surge has pushed CEO and founder Mark Zuckerberg up in the rankings of the world's wealthiest people.

Exxon, once at the top of the list, has seen its fortunes decline in recent months due to a glut of oil in the market pushing prices down and forcing layoffs throughout the industry.

It is now wrestling with Warren Buffett's Berkshire Hathaway to be one of the top five American company by market capitalization.

As of Monday morning, Facebook had a market value of $323 billion, beating out Exxon Mobil's $316 billion market cap, according to data provided to Mashable by FactSet, a financial research firm.

FB Market Cap data by YCharts

The new top four, in order: Apple, Alphabet (Google), Microsoft and Facebook. Or FAAM for short, if we're looking for acronyms.

Market caps and stock prices are fickle and ever-changing, but it is more than just a leaderboard of vanity stats. It indicates how a broad swath of Wall Street investors feel about a company's future business growth potential.

Facebook, written off by many investors immediately after going public for fear it would not be able to make money off of smaller screens, is now seen as the rare fast-growing technology company that bucks global headwinds and beats Wall Street estimates for revenue growth time and time again. It is increasingly being viewed by investors the way Apple once was — and its value is rising accordingly.

Apple, on the other hand, suddenly seems mortal. Its 13-year winning streak is ending for now as iPhone sales slowdown. And there is no other clear product in the pipeline to replace its sagging revenue growth. Even its $200 billion cash pile can't seem to convince investors of a bright future ahead.

For that reason, Apple is now on the cusp of losing its title as the world's most valuable company to.... Google.

Google, fresh with a new name and organizational structure, is seen as having numerous potential products in the pipeline that could fuel growth, a founder as CEO that is willing to make the bets to bring those to fruition and a newly hired forceful CFO to rein in expenses along the way to keep the company from going off the rails.

If Google impresses Wall Street with its earnings report on Monday afternoon, it may just be the most valuable company in the world by the time you wake up on Tuesday.