Skype has faced a number of legal challenges for its use of the word "Sky" in its logo.
The challenges have been mounted by BSkyB, Rupert Murdoch's television company, which has claimed it owns the rights to the Sky trademark.
The law suits came to light when Skype launched a bid earlier this week to raise $100 million in funding.
The filing for the initial public offering showed BSkyB had launched legal battles against the company since 2005 and, although Sky had lost cases in Switzerland, Turkey and Brazil, the European Union had held up the complaint in July.
A spokesperson from BSkyB told The Guardian: "The key contention in the dispute is that the brands Sky and Skype will be considered confusingly similar by members of the public."
"This was supported by consumer research conducted by Sky, and which was taken into account by the relevant authorities when they recently found in Sky's favour."
Although Skype hasn't released a statement since the details emerged, it wrote in the filing: "If BSkyB or other third parties were to pursue litigation to prevent our use of the Skype name or logo, defending against that litigation could be costly and time-consuming even if we were ultimately to prevail."
