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What: Shares of Liberty Global plc (LBTYA 2.67%) fell 22.2% in June 2016, according to data from S&P Global Market Intelligence. Share prices started sliding at a modest pace in the second week of the month, due to rumors of a messy acquisition about to happen in Poland. Moreover, a pending merger of Liberty Global's Dutch operations with the cable assets of telecom titan Vodafone (VOD 1.14%) was labeled "an act of desperation" as Vodafone was downgraded.

But all of that was just noise on the line by the end of the month. The vote to separate Britain from the European Union slammed Liberty Global shares like a runaway freight train. About three-quarters of June's massive plunge fell under the Brexit banner.

So what: The international cable arm of American billionaire John Malone's media empire collects 36% of its annual revenue in the U.K., which also holds the company's headquarters. Hence, British affairs are very relevant to Liberty Global's bottom line.

The Brexit vote threatens to undermine the British economy in the long run, with unpredictable effects on local consumer markets. The British Pound immediately fell 12% against the U.S. dollar, and you'll see the very direct effects of that change in Liberty Global's next earnings report.

Now what: Liberty Global's management is keeping a stiff upper lip, of course. The Vodafone deal, for example, will happen anyway.

"The deal with Vodafone is already agreed," said Liberty Global CEO Mike Fries in a Reuters interview shortly after the British vote. "It is being reviewed by EU regulators and their review should not be impacted by Brexit."

Indeed, Fries doesn't seem worried about the political headwinds at all.

"It has no immediate impact on our business and it has not reduced our appetite or interest in Europe," Fries continued. "The U.K. is a relatively large part of our business and in the end, British consumers will still want the same products and services."

Fair enough, I suppose. The political climate change is unlikely to transform British culture and consumer habits overnight. The company must still overcome the currency valuation cliff, since Liberty Global reports its results in U.S. dollars, but the underlying business is not going away.

Expect more volatility from this stock as the Brexit shock waves continue to settle. This could take a while.