Our reporting units are the same as our operating segments. In the third quarter of 2023, we reevaluated our operating segments to better align with how our chief operating decision maker ("CODM") evaluates performance and allocates resources, which resulted in a change from two operating segments—Software Products and Professional Services—to a single operating segment. As part of this reevaluation, we determined that our reporting unit is the same as our operating segment.

Before combining the reporting units, we performed a step zero qualitative assessment of the Software Products reporting unit and a step one quantitative assessment of the Professional Services reporting unit. As of June 30, 2023 and prior to the reporting unit change, goodwill attributable to the Software Products segment was $3,367.5 million and to the Professional Services segment was $9.8 million.

Our qualitative assessment for Software Products included company-specific (e.g., financial performance and long-range plans), industry, and macroeconomic factors, as well as consideration of the fair value of the reporting unit relative to its carrying value at the last valuation date (June 27, 2020). Based on our qualitative assessment, we believe it is more likely than not that the fair value of our Software Products reporting unit exceeds its carrying value and no further impairment testing is required.

Our quantitative assessment for Professional Services compared the fair value of the reporting unit to its carrying value. We estimated the fair value of the Professional Services reporting unit using a discounted cash flow valuation model. This model requires estimates of future revenues, profits, capital expenditures, working capital, and a terminal value based on a residual cash flow valuation model. We estimated this amount by evaluating historical trends, current budgets and operating plans. Based on a comparison of the estimated fair value to the carrying value of the Professional Services reporting unit as of June 30, 2023, no impairment was required.

After combining the reporting units, we performed a step zero qualitative assessment on the combined goodwill balance and determined that it is more likely than not that the fair value of the combined reporting unit exceeds its carrying value and no further impairment testing is required.

Goodwill and acquired intangible assets consisted of the following:


(in thousands)	June 30, 2023						September 30, 2022
	Gross Carrying Amount		Accumulated Amortization		Net Book Value		Gross Carrying Amount		Accumulated Amortization		Net Book Value
Goodwill (not amortized)					$	3,377,319					$	2,353,654
Intangible assets with finite lives (amortized):
Purchased software	$	617,241	$	386,917	$	230,324	$	502,859	$	355,857	$	147,002
Capitalized software		22,877		22,877		—		22,877		22,877		—
Customer lists and relationships		1,116,980		406,177		710,803		594,970		369,390		225,580
Trademarks and trade names		37,005		19,012		17,993		27,546		17,410		10,136
Other		3,912		3,912		—		3,766		3,766		—
Total intangible assets with finite lives	$	1,798,015	$	838,895	$	959,120	$	1,152,018	$	769,300	$	382,718
Total goodwill and acquired intangible assets					$	4,336,439					$	2,736,372

The aggregate amortization expense for intangible assets with finite lives is classified in our Consolidated Statements of Operations as follows:


(in thousands)	Three months ended				Nine months ended
	June 30, 2023		June 30, 2022		June 30, 2023		June 30, 2022
Amortization of acquired intangible assets	$	10,670	$	8,931	$	29,352	$	25,865
Cost of revenue		9,841		6,596		25,817		19,010
Total amortization expense	$	20,511	$	15,527	$	55,169	$	44,875