Acquired Intangible Assets and Liabilities

The following summarizes our acquired intangible assets (real estate intangibles, comprised of acquired in-place lease value, tenant relationship value and trade name along with acquired above-market lease value) and intangible liabilities (acquired below-market lease value) as of September 30, 2016 and December 31, 2015.



	Balance as of
(Amounts in thousands)	September 30, 2016			December 31, 2015
Real Estate Intangibles:
Acquired in-place lease value:
Gross amount	$	904,027		$	901,381
Accumulated amortization	(506,390		)	(472,933		)
Net	$	397,637		$	428,448
Tenant relationship value:
Gross amount	$	943,341		$	734,800
Accumulated amortization	(64,296		)	(14,495		)
Net	$	879,045		$	720,305
Trade name:
Gross amount	$	7,300		$	7,300
Accumulated amortization	(7,300		)	(417		)
Net	$	—		$	6,883
Acquired above-market leases:
Gross amount	$	111,965		$	122,311
Accumulated amortization	(87,411		)	(89,613		)
Net	$	24,554		$	32,698
Acquired below-market leases:
Gross amount	$	286,649		$	294,791
Accumulated amortization	(199,761		)	(193,677		)
Net	$	86,888		$	101,114

Amortization of acquired below-market leases, net of acquired above-market leases, resulted in an increase to rental revenues of $1.4 million and $2.2 million for the three months ended September 30, 2016 and 2015, respectively, and $5.7 million and $6.9 million for the nine months ended September 30, 2016 and 2015, respectively. The expected average remaining lives for acquired below-market leases and acquired above-market leases is 6.6 years and 4.3 years, respectively, as of September 30, 2016. Estimated annual amortization of acquired below-market leases, net of acquired above-market leases, for each of the five succeeding years and thereafter, commencing October 1, 2016 is as follows:



(Amounts in thousands)
Remainder of 2016	$	2,164
2017	7,060
2018	5,499
2019	5,659
2020	7,473
Thereafter	34,479
Total	$	62,334

Amortization of acquired in-place lease value (a component of depreciation and amortization expense) was $13.0 million and $10.1 million for the three months ended September 30, 2016 and 2015, respectively, and $40.0 million and $32.2 million for the nine months ended September 30, 2016 and 2015, respectively. The expected average amortization period for acquired in-place lease value is 7.7 years as of September 30, 2016. The weighted average remaining contractual life for acquired leases excluding renewals or extensions is 7.1 years as of September 30, 2016. Estimated annual amortization of acquired in-place lease value for each of the five succeeding years and thereafter, commencing October 1, 2016 is as follows:



(Amounts in thousands)
Remainder of 2016	$	15,000
2017	57,199
2018	50,611
2019	43,225
2020	39,199
Thereafter	192,403
Total	$	397,637

Amortization of tenant relationship value and trade names (a component of depreciation and amortization expense) was approximately $18.1 million and $0.0 million, respectively, for the three months ended September 30, 2016 and approximately $49.8 million and $6.9 million, respectively, for the nine months ended September 30, 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 September 30, 2016, the weighted average remaining contractual life for customer contracts was 12.5 years. Estimated annual amortization of customer contracts for each of the five succeeding years and thereafter, commencing October 1, 2016 is as follows:



(Amounts in thousands)
Remainder of 2016	$	19,122
2017	74,412
2018	74,412
2019	74,412
2020	74,412
Thereafter	562,275
Total	$	879,045