South Korean mobile operators fear a Supreme Court ruling requiring them to disclose their operating costs could expose trade secrets, The Korea Herald reported.

The country’s high court upheld a ruling which said public access to information about operating costs is a right granted by the constitution for consumers to have a better understanding of the fees operators charge. The ruling requires the country’s three mobile operators to provide a breakdown of their income statements and sales-related data for 2G and 3G services provided between 2005 and 2011.

SK Telecom and LG Uplus expressed concern the high court ruling could unveil confidential information, The Korea Herald said.

An industry source told the newspaper that making mobile carriers’ unit costs public is an almost unprecedented case worldwide.

A local activist group in 2011 petitioned the Korea Communications Commission to require mobile players to release the cost information, but the commission rejected the request, arguing the figures could contain classified data. The group later filed a lawsuit.

Although the ruling is limited to 2G and 3G services offered from 2005 to 2011, operators are concerned about rising pressure from the government and the public to reduce fees.

Ahn Jin-geol, leader of People’s Solidarity for Participatory Democracy, at a press conference asked operators to voluntarily make their 4G service costs public, The Korea Herald reported.

“If the companies and government do not disclose the LTE costs voluntarily, we will take additional steps to demand they are revealed,” Ahn said.