Nevertheless, in Portugal, the main market segment for GSM-operators is the segment of national calls. Moreover it appears that at least half the costs of mobile operators in handling calls are traffic-insensitive costs. It cannot therefore be ruled out that a mobile operator, in order to increase overall turnover, usage of its network and market share, would allot a higher share of these traffic-insensitive costs to national calls and offer international tariffs which are at the same level as the current international tariffs of Portugal Telecom.
