Google parent Alphabet Inc has reported a 20.2 per cent rise in quarterly revenue, helped by robust sales of advertising on mobile devices and YouTube, and the search company authorised a $US7 billion ($A9.2 billion) repurchase of its Class C stock.
Alphabet, along with Facebook Inc, dominates the fast-growing mobile advertising market.
Shares of Alphabet, the world's No. 2 company by market value, were up 1.6 per cent in after-hours trading.
Google has been dogged by concerns about how it would nudge its vast web advertising business toward mobile, but the company's recent performance has reassured Wall Street that the transition is well underway, said analyst Kerry Rice of Needham & Co.
"They are just one of the best positioned companies for the future of the internet," Rice said.
Google's ad revenue rose 18.1 per cent to $US19.82 billion ($A26.11 billion) in the third quarter, accounting for 89.1 per cent of Google's total revenue, compared with 89.8 per cent of revenue in the second quarter.
Google's Other Revenue, which includes the company's increasingly important cloud business, jumped 38.8 per cent after rising 33 per cent in the second quarter.
Up to Thursday's close of $US817.35 ($A1,076.61), Alphabet's shares had risen 5.1 per cent since the start of the year.
