Google's parent company posted strong earnings after stock markets closed on Monday, numbers that were good enough to push its stock up enough to make the company worth more than Apple.

Alphabet Inc. posted earnings of $8.67 US per share on revenue of $21.33 billion. Analysts had been expecting the company to post a profit of $8.10 per share.

The strong showing was enough to push Alphabet's shares up six per cent in after-hours trading, valuing the company at more than $554 billion US. That makes the corporate entity formerly known as Google Inc. and now known as Alphabet Inc. worth more than Apple, which was previously the most valuable public company in the world at $535 billion.

"This makes Alphabet an even stronger bellwether for investors to watch," Scott Fullman, chief strategist at Revere Securities Corp, said after the earnings report came out. "The company has been tracking very well given the volatility in the market, dominated by falling energy prices and weakness from China."

The online company said its revenue from search ads rose 31 per cent in the fourth quarter compared to the same period a year earlier.

Monday's results are the first time that Alphabet has broken its numbers into two segments β€” money earned in the core Google internet search and advertising business, plus everything else.

"Under the previous setup at Google, "things had always been a little muddy," said Edward Jones analyst Josh Olson. "The hope now is that management will continue to show greater cost discipline."

The things in that second category tend to draw a lot of attention, but their financial numbers were not as impressive as the Google segment's were. The business segment Alphabet classifies as "other bets" includes projects linked to artificial intelligence, self-driving cars and health technology, and they continue to lose money, the numbers showed.

Although they took in $448 million US in revenue during the quarter, those projects collectively lost $3.5 billion during the quarter. That compares to a loss of $1.9 billion a year earlier.

With files from Reuters