NOTE 12 — INTANGIBLE ASSETS

Intangible assets consist mainly of relationships recognized upon business combinations and software development, with application in the management of the business:

	Supplier relationships		Software development		Customer contracts and relationships		Others		Total
Balance as of January 1, 2015	56,654		688,061		749,027		53,356		1,547,098

Foreign exchange effect	—		123,167		327,424		14,375		464,966
Acquisition	—		118,933		—		7,495		126,428
Disposal	—		(1,182	)	—		(4,208	)	(5,390	)
Amortization	(9,083	)	(120,497	)	(164,968	)	(2,793	)	(297,341	)

Balance as of December 31, 2015	47,571		808,482		911,483		68,225		1,835,761

Foreign exchange effect	—		(60,464	)	(140,812	)	(7,509	)	(208,785	)
Acquisition	—		40,643		—		13,401		54,044
Disposal	—		(2,145	)	—		(13,050	)	(15,195	)
Amortization	(7,845	)	(149,911	)	(155,063	)	(5,316	)	(318,135	)
(-) Effect of selling of subsidiary	—		—		—		(27,749	)	(27,749	)

Balance as of December 31, 2016	39,726		636,605		615,608		28,002		1,319,941

Foreign exchange effect	—		2,947		3,835		884		7,666
Acquisition	—		37,939		—		—		37,939
Disposal	—		—		(27,652	)	—		(27,652	)
Amortization	(6,940	)	(149,150	)	(125,621	)	(3,486	)	(285,197	)
(-) Assets held for sale (note 3.4)	—		(37,512	)	(25,396	)	(17,700	)	(80,608	)

Balance as of December 31, 2017	32,786		490,829		440,774		7,700		972,089


Estimated useful lives	5 to 20 years		7 years		5 to 20 years		5 years

The composition of other intangible assets by segment is as follows:

	2017	2016	2015
Brazil	351,578	412,134	459,383
Special Steel	152,640	219,878	357,435
South America	1,863	7,606	13,507
North America	466,008	680,323	1,005,436

	972,089	1,319,941	1,835,761