What: Information-technology service company BT Group (NYSE:BT) plummeted as much as 19.4% on Friday following the United Kingdom of Great Britain's vote to exit the European Union, or a vote being referred to as "Brexit." Shares ended the trading day down 18.2%.

Image source: BT Group.

So what: While Britain banks were hit hard on Friday as global markets face uncertainty about what Brexit means for the British economy, many British-based tech companies with multinational operations were hit hard, too. Investors are concerned that information-technology companies like BT Group could lose their unrestricted access to the EU, and hence make competing with other EU companies difficult.

BT Group is a communications-services company with multinational reach, and many investors may be wondering if the company's information-technology services will be at a disadvantage, or even compromised.

Now what: The implications of the Brexit and how it will impact companies like BT Group are still unclear. Perhaps BT Group will provide a press release detailing how management plans to navigate through this uncertain time.

Daniel Sparks has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.