Facebook is growing increasingly worried about the impact that ad blocking technology is having on its revenues, a new regulatory filing by the company has revealed.

The filing, made with Americas Securities and Exchange Commission, states that “revenue generated from the display of ads on personal computers has been impacted by these technologies from time to time. As a result, these technologies have had an adverse effect on our financial results and, if such technologies continue to proliferate, in particular with respect to mobile platforms, our future financial results may be harmed.”

Facebook has expressed concerns about changing technologies and the impact they could have on ad revenues in the past, but never in this detail. While the statement specifically cites desktop computers as the current concern, its possible that the introduction of ad blocking apps on iOS 9 has led to their elevated level of worry.

According to the companys Q3 earnings, 95 per cent of Facebooks revenue per user comes from advertising, meaning that anything that has a significant impact on those revenues should set off alarms for the social network.

The same figures show that 78 per cent of its ad revenue comes from mobile devices, so the growth of mobile ad blockers and content blocking services should be of particular concern to Facebook, as even a one per cent increase in the number of users employing such measures could have a massive impact on the firms income.