Acquired Intangible Assets and Liabilities

6 Months Ended

Jun. 30, 2011

Acquired Intangible Assets and Liabilities

Acquired Intangible Assets and Liabilities

4. Acquired Intangible Assets and Liabilities

The following summarizes our acquired intangible assets (acquired in place lease value and acquired above-market lease value) and intangible liabilities (acquired below-market lease value) as of June 30, 2011 and December 31, 2010.

	Balance as of
(Amounts in thousands)	June 30, 2011			December 31, 2010
Acquired in place lease value:
Gross amount	$	518,357		$	515,958
Accumulated amortization		(290,853	)		(261,978	)
Net	$	227,504		$	253,980
Acquired above-market lease value:
Gross amount	$	88,126		$	87,622
Accumulated amortization		(53,620	)		(47,083	)
Net	$	34,506		$	40,539
Acquired below-market lease value:
Gross amount	$	191,940		$	189,990
Accumulated amortization		(107,422	)		(96,740	)
Net	$	84,518		$	93,250

Amortization of acquired below-market lease value, net of acquired above-market lease value, resulted in an increase to rental revenues of $1.9 million and $2.4 million for the three months ended June 30, 2011 and 2010, respectively, and $3.7 million and $4.7 million for the six months ended June 30, 2011 and 2010, respectively. The expected average remaining lives for acquired below-market leases and acquired above-market leases is 4.8 years and 3.6 years, respectively, as of June 30, 2011. Estimated annual amortization of acquired below-market lease value, net of acquired above-market lease value, for each of the five succeeding years, commencing January 1, 2012 is as follows:

(Amounts in thousands)
2012	$	6,546
2013		7,115
2014		5,754
2015		5,088
2016		4,208

Costs associated with extending or renewing acquired leases are capitalized as exercised and classified as deferred leasing cost. Amortization of acquired in place lease value (a component of depreciation and amortization expense) was $13.5 million and $10.2 million for the three months ended June 30, 2011 and 2010, respectively, and $27.8 million and $20.1 million for the six months ended June 30, 2011 and 2010, respectively. The expected average amortization period for acquired in place lease value is 4.5 years as of June 30, 2011. The weighted average period prior to the next renewal or extension related to remaining contractual life for acquired leases is 3.9 years as of June 30, 2011. Estimated annual amortization of acquired in place lease value for each of the five succeeding years, commencing January 1, 2012 is as follows:

(Amounts in thousands)
2012	$	42,321
2013		37,960
2014		33,062
2015		24,816
2016		16,371