Acquired Intangible Assets and Liabilities

The following summarizes our acquired intangible assets (real estate intangibles, comprised of acquired in-place lease value and tenant relationship value along with acquired above-market lease value) and intangible liabilities (acquired below-market lease value) as of March 31, 2017 and December 31, 2016.



	Balance as of
(Amounts in thousands)	March 31, 2017			December 31, 2016
Real Estate Intangibles:
Acquired in-place lease value:
Gross amount	$	898,904		$	896,693
Accumulated amortization	(532,545		)	(517,443		)
Net	$	366,359		$	379,250
Tenant relationship value:
Gross amount	$	975,188		$	971,519
Accumulated amortization	(99,926		)	(82,069		)
Net	$	875,262		$	889,450
Acquired above-market leases:
Gross amount	$	110,748		$	110,142
Accumulated amortization	(89,922		)	(87,961		)
Net	$	20,826		$	22,181
Acquired below-market leases:
Gross amount	$	284,695		$	283,899
Accumulated amortization	(206,054		)	(202,000		)
Net	$	78,641		$	81,899

Amortization of acquired below-market leases, net of acquired above-market leases, resulted in an increase to rental revenues of $1.8 million and $2.3 million for the three months ended March 31, 2017 and 2016, respectively. The expected average remaining lives for acquired below-market leases and acquired above-market leases is 6.3 years and 4.0 years, respectively, as of March 31, 2017. Estimated annual amortization of acquired below-market leases, net of acquired above-market leases, for each of the five succeeding years and thereafter, commencing April 1, 2017 is as follows:



(Amounts in thousands)
Remainder of 2017	$	5,179
2018	5,538
2019	5,680
2020	7,434
2021	7,423
Thereafter	26,561
Total	$	57,815

Amortization of acquired in-place lease value (a component of depreciation and amortization expense) was $14.2 million and $13.7 million for the three months ended March 31, 2017 and 2016, respectively. The expected average amortization period for acquired in-place lease value is 8.0 years as of March 31, 2017. The weighted average remaining contractual life for acquired leases excluding renewals or extensions is 6.9 years as of March 31, 2017. Estimated annual amortization of acquired in-place lease value for each of the five succeeding years and thereafter, commencing April 1, 2017 is as follows:



(Amounts in thousands)
Remainder of 2017	$	40,295
2018	47,854
2019	40,648
2020	36,692
2021	34,077
Thereafter	166,793
Total	$	366,359

Amortization of tenant relationship value and trade names (a component of depreciation and amortization expense) was approximately $17.6 million and $0.0 million, respectively, for the three months ended March 31, 2017 and approximately $15.9 million and $0.5 million, respectively, for the three months ended March 31, 2016. During the quarter ended June 30, 2016, management of the Company decided to retire the Telx trade name. Accordingly, the Company wrote off the net remaining balance of approximately $6.1 million. As of March 31, 2017, the weighted average remaining contractual life for customer contracts was 12.7 years. Estimated annual amortization of customer contracts for each of the five succeeding years and thereafter, commencing April 1, 2017 is as follows:



(Amounts in thousands)
Remainder of 2017	$	52,687
2018	70,249
2019	70,249
2020	70,249
2021	70,249
Thereafter	541,579
Total	$	875,262