Silicon Valley tycoons Mark Zuckerberg, Jeff Bezos and Elon Musk have seen their personal fortunes dwindle by billions of dollars after a backlash sent technology stocks spiralling.

Under-fire Facebook chief executive Zuckerberg's wealth has plunged by US$10.2 billion ($14b), or 14 per cent, to US$65.1b in the wake of the personal data scandal engulfing the social media giant, according to the Daily Telegraph.

Amazon founder Bezos, the world's richest man, has seen his fortune shrink by just under US$10b to US$121b after Donald Trump took aim at the e-commerce firm, while Musk's fortune has dropped by US$2b to US$18.5b, a 9.8 per cent tumble.

Some US$270b was wiped off the value of the so-called FANG stocks of Facebook, Amazon, Netflix and Google (Alphabet) in just eight days amid concerns that governments could impose tighter regulation on personal data.

Advertisement

Tech stocks started to claw back lost ground on Thursday ahead of the Easter break but it was not enough to restore the billions lost.

Fears were ignited by revelations that British political marketing firm Cambridge Analytica had harvested the private data of 50 million Facebook users to allegedly target voters.

Amazon's share slide was extended by Trump criticising the e-commerce mammoth for paying "little or no taxes" and putting "many thousands of retailers out of business".

Tesla's share price plunged 12 per cent after questions were raised over the car pioneer's semi-autonomous vehicles following a fatal crash.