The changes in the carrying amount of goodwill reported in our segments were as follows:

(1)

Relates to the acquisitions of: a) RobustWealth, a financial technology company, which is consolidated within our Corporate segment with the majority of the goodwill allocated to our Principal Global Investors segment; b) INTERNOS, a London-based European real estate investment manager that, upon acquisition, became Principal Real Estate Europe Limited and is consolidated within our Principal Global Investors segment; c) MetLife Afore, S.A. de C.V., which was MetLife, Inc.’s pension fund management business in Mexico and is consolidated within our Principal International segment.

(2)	Relates to sales of closed blocks of business in Mexico.

(3)

Relates to the acquisitions of: a) Wells Fargo Institutional Retirement & Trust business consolidated within our Retirement and Income Solutions segment; b) a consolidating interest in Finisterre Capital LLP within our Principal Global Investors segment for which we previously held an equity method interest; c) measurement period adjustments related to RobustWealth within our Principal Global Investors segment and Corporate segment.

(4)	Relates to the movement of our investment management company in Brazil from the Principal International segment to the Principal Global Investors segment.

On July 1, 2019, we completed the purchase of the Institutional Retirement & Trust business of Wells Fargo Bank, N.A. (the “Acquired Business”), which includes defined contribution, defined benefit, executive deferred compensation, employee stock ownership plans, institutional trust and custody, and institutional asset advisory businesses. The purchase price consisted of $1.2 billion cash paid at closing, which was funded with available cash and debt financing. See “Note 9, Debt” for further information on the debt financing. An additional earn-out payment of up to $150.0 million may be payable based upon the retention of fee revenue of the Acquired Business through December 31, 2020.

The fair value of the net assets acquired primarily relates to intangible assets. Of the acquired intangible assets, $618.5 million was assigned to goodwill and is not subject to amortization. The goodwill is largely related to the opportunities to realize substantial revenue and cost synergies while achieving scale in operations.

Of the remaining acquired intangible assets, $510.3 million was assigned to customer relationships, which are subject to amortization over a 23-year useful life, and $35.4 million was assigned to technology, which is subject to amortization over a 6-year useful life.

2. Goodwill and Other Intangible Assets – (continued)

Finite Lived Intangible Assets

Amortized intangible assets primarily relate to customer relationship intangibles associated with the Acquired Business and previous acquisitions in Chile, Mexico and Hong Kong. The finite lived intangible assets that continue to be subject to amortization over a weighted average remaining expected life of 18 years were as follows:


	December 31,
	2019		2018
	(in millions)
Gross carrying value	$	1,346.3	$	810.2
Accumulated amortization		343.2		288.4
Net carrying value	$	1,003.1	$	521.8

The amortization expense for intangible assets with finite useful lives was $62.8 million, $53.9 million and $45.4 million for 2019, 2018 and 2017, respectively. As of December 31, 2019, the estimated amortization expense for the next five years is as follows (in millions):


Year ending December 31:
2020	$	74.5
2021		73.2
2022		72.4
2023		70.2
2024		69.0

Indefinite Lived Intangible Assets

The net carrying amount of unamortized indefinite lived intangible assets was $783.6 million and $793.3 million as of December 31, 2019 and 2018, respectively. As of both December 31, 2019 and 2018, $608.0 million relates to investment management contracts associated with our acquisition of WM Advisors, Inc. in 2006. The remaining balance primarily relates to the trade name intangible associated with our acquisition of Administradora de Fondos de Pensiones Cuprum S.A. in 2013.