And the fourth biggest company by market cap.
In a move that’s all too indicative of the markets today, Facebook surpassed Exxon in market cap as of midday Monday.
The social network’s worth has skyrocketed in the five days since it delivered a blockbuster earnings report that revealed a 51.7% jump in revenue and a 14% increase in active monthly users. New ad formats and an improved mobile app helped boost sales.
Those results helped boost CEO Mark Zuckerberg’s net worth to make him the sixth richest person on Earth.
Exxon, meanwhile, has experienced a near opposite fate. Its value has fallen due to the global glut of oil that has pushed prices down to record lows.
Facebook’s surge in market cap has reshuffled the companies atop the world’s most valuable list. The social network now ranks fourth behind No. 1 Apple aapl , No. 2 Alphabet (or Google) googl , and No. 3 Microsoft msft . Exxon is now neck-and-neck with Warren Buffett’s Berkshire Hathaway brk.a for fifth place.