Big Tech is facing its biggest challenge in decades as antitrust regulators on both sides of the Atlantic crack down on alleged anti-competitive practices that could result in break-up orders to Apple and Alphabet’s Google, a first for the industry.

That in turn could inspire watchdogs around the world to pile on, as evidenced in the growing number of antitrust probes in various countries following the opening of EU and U.S. cases. Since AT&T was broken up exactly 40 years ago, no company has faced the possibility of a regulator-led break-up in the United States until now.

(EU antitrust chief Margrethe Vestager) said that requiring Google to sell some of its assets seemed to be the only way to avoid conflicts of interest as it would prevent Google from allegedly favouring its own online digital advertising technology services versus advertisers and online publishers.

Apple’s highly integrated system would also make a break-up difficult compared with Google, said lawyer Damien Geradin at Geradin Partners, who is advising several app developers in other cases against Apple.

“It seems to me much more complicated. You are talking about something that is integrated, for example you can’t force Apple to divest its App Store. That doesn’t make sense,” he said.