Google parent Alphabet unveiled a $70 billion share buyback and beat quarterly revenue estimates Thursday, benefiting from steady growth in its digital advertising business, which helped offset muted growth at its cloud computing unit.

Shares of the company jumped 6% in extended trading.

U.S. President Donald Trump's trade policy has triggered worries of an economic downturn, prompting companies to rethink their spending on advertising. But analysts say the digital ad market still held its ground in the first quarter.

Revenue from Google's mainstay ad business, which makes up about 75% of its overall revenue, rose 8.5% to $66.89 billion in the quarter — a slowdown from the prior quarter's 10.6% increase, but still above analysts' expectations for a rise of 7.7%.

Google Cloud reported a 28% rise in revenue to $12.26 billion, slowing from the 30.1% growth reported in the previous quarter. Analysts were expecting the unit to report revenue of $12.27 billion, according to LSEG's data compilation.

The company reported total revenue of $90.23 billion for the first quarter, compared to analysts' average estimate of $89.12 billion, according to data compiled by LSEG.