7. Intangible assets, net
Intangible assets, net as of December 31 were:


in $ millions	2025	2024
Marketing-related	349	337
Customer-related (i)	1,493	1,394
Contract-based (ii)	969	110
Software costs	202	126
IT projects in progress	79	63
Total intangible assets, gross	3,092	2,030
Accumulated amortization	(1,044)	(819)
Total intangible assets, net	2,048	1,211

(i) The customer-related intangible assets relate predominantly to non-contractual customer relationships.

(ii) Contract-based intangible assets of $789 million related to supply agreements arose on the acquisition of Eco Material in September 2025.

Amortization of intangibles included predominantly in Selling, general and administrative expenses in the Consolidated Statements of Income for the years ended December 31, 2025, 2024 and 2023 amounted to $192 million, $152 million and $139 million, respectively.

The estimated amortization for intangible assets for the five years subsequent to December 31, 2025, and thereafter is as follows:


in $ millions	2026	2027	2028	2029	2030	2031 and thereafter
Amortization	218	176	156	139	117	1,242