Goodwill and Other Intangible Assets

The changes in the carrying amount of goodwill by segment for the nine months ended September 29, 2018, are as follows:



(Amounts in millions)	Commercial & Industrial Group			Snap-on Tools Group		Repair Systems & Information Group			Total
Balance as of December 30, 2017	$	298.4		$	12.5	$	613.2		$	924.1
Currency translation	(8.8		)	—		(5.5		)	(14.3		)
Acquisitions and related adjustments	4.1			—		—			4.1
Balance as of September 29, 2018	$	293.7		$	12.5	$	607.7		$	913.9

Goodwill of $913.9 million as of September 29, 2018, includes: (i) $25.1 million from the acquisition of Norbar, (ii) $2.6 million from the acquisition of Fastorq, and (iii) $2.0 million from the acquisition of TCS. The goodwill from the Norbar, Fastorq and TCS acquisitions is included in the Commercial & Industrial Group. See Note 3 for additional information on acquisitions.

Additional disclosures related to other intangible assets are as follows:



	September 29, 2018					December 30, 2017
(Amounts in millions)	Gross Carrying Value		Accumulated Amortization			Gross Carrying Value		Accumulated Amortization
Amortized other intangible assets:
Customer relationships	$	173.5	$	(105.6	)	$	175.2	$	(98.2	)
Developed technology	18.8		(18.5		)	18.9		(18.4		)
Internally developed software	182.9		(142.9		)	177.0		(133.4		)
Patents	35.0		(22.9		)	34.1		(22.7		)
Trademarks	3.1		(1.9		)	3.0		(2.0		)
Other	7.4		(2.9		)	7.7		(2.7		)
Total	420.7		(294.7		)	415.9		(277.4		)
Non-amortized trademarks	111.8		—			115.2		—
Total other intangible assets	$	532.5	$	(294.7	)	$	531.1	$	(277.4	)

Snap-on completed its annual impairment testing of goodwill and other indefinite-lived intangible assets in the second quarter of 2018, the results of which did not result in any impairment. Significant and unanticipated changes in circumstances, such as declines in profitability and cash flow due to significant and long-term deterioration in macroeconomic, industry and market conditions, the loss of key customers, changes in technology or markets, significant changes in key personnel or litigation, a significant and sustained decrease in share price and/or other events, including effects from the sale or disposal of a reporting unit, could require a provision for impairment of goodwill and/or other intangible assets in a future period. As of September 29, 2018, the company had no accumulated impairment losses.

The weighted-average amortization periods related to other intangible assets are as follows:



	In Years
Customer relationships	15
Developed technology	3
Internally developed software	4
Patents	8
Trademarks	6
Other	39

Snap-on is amortizing its customer relationships on both an accelerated and straight-line basis over a 15-year weighted-average life; the remaining intangibles are amortized on a straight-line basis. The weighted-average amortization period for all amortizable intangibles on a combined basis is 11 years.

The company’s customer relationships generally have contractual terms of three to five years and are typically renewed without significant cost to the company. The weighted-average 15-year life for customer relationships is based on the company’s historical renewal experience. Intangible asset renewal costs are expensed as incurred.

The aggregate amortization expense was $6.2 million and $19.2 million for the respective three and nine months ended September 29, 2018, and $7.1 million and $20.7 million for the respective three and nine months ended September 30, 2017. Based on current levels of amortizable intangible assets and estimated weighted-average useful lives, estimated annual amortization expense is expected to be $25.4 million in 2018, $23.2 million in 2019, $19.3 million in 2020, $16.0 million in 2021, $14.4 million in 2022, and $12.5 million in 2023.