Google surpasses Apple as world's most valuable company

For the fourth quarter, Alphabet raked in $21.3 billion in total sales and adjusted profits of $8.67 for every Class A share, the company said in a prepared statement. Total sales were up 18 year over year, while advertising revenue was up 17 percent for the same period.

Shares popped after Alphabet's announcement, rising 1.22 percent to hit $752 per share in normal trading with a market capitalization of $517.17 billion. The stock kept rising after the bell, at one point touching $813 per share, bringing its market cap up to $559.13 billion. Apple ended the day down at $96.43 with a market cap of $538.7 billion.

Alphabet is seeing a renaissance in growth as its advertising business made big gains this quarter. The company's services division also saw wider adoption including Gmail, which passed one billion users in quarter four. Under the Alphabet umbrella, Google's "moonshot" projects" — Wi-Fi balloons, self-driving cars, glucose-reading contact lenses, human longevity — saw advancements, but cost the firm more than $3.56 billion over the last three months of 2015.