Image source: Luxoft Holding Inc.

What: Shares of Luxoft holding Inc. (NYSE:LXFT) fell 10.4% Friday as the market fretted over the effects of the Brexit on the Switzerland-based software-development and IT-solutions company.

So what: Luxoft isn't alone today, as the U.K.'s vote to leave the European Union caused a broad market sell-off. But the political and economic uncertainty caused by the development left investors disproportionately stepping away from companies with European exposure like Luxoft, which generated more than a third of its total revenue from clients in the U.K. during the past year.

Now what: Luxoft was rightly pleased with the strong momentum its business demonstrated as it turned in better-than-expected fiscal fourth-quarter results last month, marking its 16th straight year of achieving what CFO Roman Yakushkin described as "strong revenue growth and profitability." With that in mind, I feel the need to stress that the repercussions of the Brexit remain unclear, and firmly believe that shareholders would do well to remain calm, and focus first on the fundamentals driving the businesses underlying their investments.