Switzerland’s leading telephone company Swisscom AG, has been fined SF333.4m (£138.51m) by the country’s competition watchdog for overcharging rivals including France Telecom SA’s Orange unit.

According to the Swiss Competition Commission, Swisscom enjoyed a “dominant position” in the market and imposed an “unfair” call termination charge of 33.5 centimes. The fine represents a significant reduction from a previously announced SF489m penalty from a draft ruling in April last year.

Swisscom has rejected the charges and said Friday that it intends to fight the decision in court.

Switzerland began investigating the fees its three mobile operators charge each other for routing calls to their networks four years ago.

“Swisscom Mobile is not exposed to significant competitive pressure from consumer markets,” the watchdog said in a statement Friday.