Acacia’s only identifiable intangible assets at September 30, 2014 and December 31, 2013 are patents. Patent-related accumulated amortization totaled $152,838,000 and $112,323,000 as of September 30, 2014 and December 31, 2013, respectively.

Acacia’s patents have remaining estimated economic useful lives ranging from one to ten years. The weighted-

average remaining estimated economic useful life of Acacia’s patents is approximately six years. The following table presents the scheduled annual aggregate amortization expense as of September 30, 2014 (in thousands):



Remainder of 2014	$	12,636
2015	49,110
2016	46,011
2017	44,904
2018	40,789
Thereafter	75,985
Total	$	269,435

For the nine months ended September 30, 2014 and 2013, Acacia paid patent related investment costs totaling $24,518,000 (including up-front patent portfolio advances and previously accrued milestone payments related to patent related investments made in prior periods) and $10,416,000, respectively. The underlying patents have estimated economic useful lives of approximately four to ten years. Included in net additions to capitalized patent costs during the nine months ended September 30, 2014 and 2013 are accrued patent investment costs totaling $2,000,000 and $9,750,000, respectively, which are amortized over the estimated economic useful life of the related patents.

During the nine months ended September 30, 2014 and 2013, certain operating subsidiaries recovered up-front patent portfolio advances from applicable net licensing proceeds prior to the scheduled amortization of such up-front patent portfolio advances, resulting in the acceleration of amortization expense for the applicable patent related assets. Accelerated amortization expense related to the recovery of up-front patent portfolio advances totaled $1,186,000 and $593,000 for the nine months ended September 30, 2014 and 2013, respectively. During the periods presented, certain Acacia operating subsidiaries elected to terminate or sell their rights to patent portfolios, resulting in the acceleration of amortization expense for the patent-related assets totaling $2,702,000 and $1,631,000 for the nine months ended September 30, 2014 and 2013, respectively. Proceeds from the sale of patents for the nine months ended September 30, 2014 were $3,500,000.

Included in amortization of patents for the nine months ended September 30, 2014 was accelerated amortization related to the partial write-down of a patent portfolio, due to a reduction in expected estimated future net cash flows, totaling $2,565,000.