(Bloomberg Opinion) — It hasn’t even been two weeks since news outlets started to report that U.S. antitrust authorities were carving up their turf to pursue possible monopoly investigations into Google, Facebook Inc. and other U.S. technology titans.
Investors panicked for a day, but the regulatory risk has settled into background noise. It’s this nagging but probably-not-immediately-terrible danger.

That assessment is most likely correct. The wheels of justice move slowly in Washington and other world capitals. But there was a reminder on Wednesday of just how dangerous it can be when government investigators start digging.

The Wall Street Journal reported that people at Facebook Inc. are concerned about internal emails that appear to show Mark Zuckerberg did not prioritize compliance with a 2012 U.S. Federal Trade Commission agreement to better protect people’s digital privacy.

Those emails were unearthed as part of the FTC’s continuing investigation into whether Facebook’s more recent privacy missteps violated that 2012 consent decree. Any direct involvement by Zuckerberg in not taking seriously users’ digital privacy would be embarrassing to Facebook, of course, and it could compel the FTC to try harder to name Zuckerberg personally in any new settlement with the agency. (A Facebook representative told Bloomberg News that Zuckerberg and other company employees did not “knowingly violate the company’s obligations” with the FTC agreement.)

The episode also shows the danger of investigations, whether it is Facebook’s multiple run-ins or the potential future antitrust investigations into U.S. tech superpowers. History has shown that it is hard to predict what people with government mandates might find that could embarrass a company or provide evidence of legal violations.

Bill Gates’s inbox was practically a star witness in the U.S. government’s antitrust case against Microsoft Corp. that started in 1998. Do you think Gates would be the only tech executive to write candid emails that appeared to bully allies and rivals to do what Microsoft wanted, or talk about cutting off competitors’ “air supply,” to cite from evidence in the U.S. government’s ultimately unsuccessful effort to break up the company?

More recently, FTC staff pursuing a possible antitrust case against Google dug up documents that showed the company boosted its own services and demoted rival comparison shopping websites in search result tests. FTC staff also quoted Google’s top economist, Hal Varian, saying that the company’s web search popularity was higher than outside researchers had estimated. “From an antitrust perspective, I’m happy to see them underestimate our share,” he said, according to portions of the FTC staff report later released accidentally.

Armed with evidence like this, FTC staff recommended suing Google for three potentially anticompetitive business practices and said it was a “close call” against concluding that Google’s preferential treatment of its own services violated antitrust law. FTC commissioners ultimately voted to close the investigation without taking action, and Google agreed to some voluntary changes.

Just last month, internal company documents came back to bite another U.S. technology giant. A U.S. federal judge ruled against Qualcomm Inc. in an antitrust case and said she believed the contents of Qualcomm executives’ emails, notes and other materials more than their court testimony. The chipmaker disagreed with the judge’s decision and her assessment of its executives’ credibility.

Government probes are unpredictable at best because no one knows what they will find. As U.S. antitrust enforcers knock on Big Tech’s doors again, the companies and their investors may not be afraid enough of what is lurking in those in-boxes.