3 Operating costs

Direct costs

In CHF million	1.1.–30.6.2018	1.1.–30.6.2017
Customer premises equipment and merchandise	544	511
Services purchased	279	210
Costs of obtaining a contract	172	141
Costs to fulfill a contract	24	–
Traffic fees of foreign subsidiaries	216	179
International traffic fees	111	117
National traffic fees	50	55
Total direct costs	1,396	1,213

Indirect costs

In CHF million	1.1.–30.6.2018	1.1.–30.6.2017
Salary and social security expenses	1,406	1,454
Other personnel expense	31	37
Total personnel expense	1,437	1,491

Information technology cost	136	143
Maintenance expense	150	128
Rental expense	100	101
Energy costs	55	54
Advertising and selling expenses	93	110
Consultancy expenses and freelance workforce	89	80
Administration expense	50	54
Allowances for receivables	37	44
Miscellaneous operating expenses	333	293
Total other operating expense	1,043	1,007

Capitalised self-constructed assets	(167)	(158)
Gain on sale of property, plant and equipment	(4)	(1)
Miscellaneous income	(43)	(122)
Total capitalised self-constructed assets and other income	(214)	(281)

Total indirect costs	2,266	2,217

Capitalised costs of self-constructed assets include personnel costs for the production of technical installations, the construction of network infrastructures and the development of software for internal use.