The following disclosure of estimated fair value was determined by management using available market information and appropriate valuation methodologies. However, considerable judgment is necessary to interpret market data and develop estimated fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company could realize on disposition of the assets and liabilities at September 30, 2019 and December 31, 2018. The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts.

Cash equivalents, receivables, notes receivables, accounts payable, and accrued expenses and other liabilities are carried at amounts which reasonably approximate their fair values as of September 30, 2019 and December 31, 2018.

The fair value of the Company’s long-term debt, consisting of senior unsecured notes, unsecured term loans, an unsecured revolving credit facility and mortgages, loans payable and other obligations aggregated approximately $3,127,626,000 and $2,711,712,000 as compared to the book value of approximately $3,151,561,000 and $2,792,651,000 as of September 30, 2019 and December 31, 2018, respectively. The fair value of the Company’s long-term debt was categorized as a level 3 basis (as provided by ASC 820, Fair Value Measurements and Disclosures). The fair value was estimated using a discounted cash flow analysis valuation based on the borrowing rates currently available to the Company for loans with similar terms and maturities. The fair value of the mortgage debt and the unsecured notes was determined by discounting the future contractual interest and principal payments by a market rate. Although the Company has determined that the majority of the inputs used to value its derivative financial instruments fall within level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivative financial instruments utilize level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. The Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivative financial instruments. As a result, the Company has determined that its derivative financial instruments valuations in their entirety are classified in level 2 of the fair value hierarchy.

The fair value measurements used in the evaluation of the Company’s rental properties are considered to be Level 3 valuations within the fair value hierarchy, as there are significant unobservable inputs. Examples of inputs that were utilized in the fair value calculations include estimated holding periods, discount rates, market capitalization rates, expected lease rental rates, and third party broker information.

Valuations of rental property identified as held for sale are based on estimated sale prices, net of estimated selling costs, of such property.

The Company identified as held for sale three office properties, three multi-family rental properties and one retail pad as of September

30, 2019 with an aggregate carrying value for the rental property of $419.2 million. The total estimated sales proceeds, net of expected selling costs, from the sales are expected to be approximately $536.6 million. The Company determined that the carrying value of two of the properties was not expected to be recovered from estimated net sales proceeds and accordingly recognized an unrealized loss allowance of $35.1 million during the three months ended September 30, 2019.

As part of its ongoing portfolio assessment process, the Company made the decision to pursue selling a 317,040 square foot office property. The Company evaluated the recoverability of the carrying value of this property and determined that due to the shortening of the expected period of ownership, it was necessary to reduce the carrying value of the property to its estimated fair value. Accordingly, the Company recorded a valuation impairment charge of $5.8 million at June 30, 2019.

Additionally, at September 30, 2019, the Company evaluated the recoverability of the carrying value of certain properties and undeveloped land, being considered for sale in the short or medium term and determined that due to the potential shortening of the expected period of ownership, it was necessary to reduce the carrying value of the properties and land to their estimated fair values. The Company also recorded an impairment charge of $451,000 on miscellaneous investments. Accordingly, the Company recorded a property impairment charge of $5.9 million and land and other impairment charges of $6.1 million at September 30, 2019.

The Company owns two separate developable land parcels in Conshohocken and Bala Cynwyd, Pennsylvania, that were being considered for development into multi-family rental properties. During the fourth quarter 2018, the Company made the decision to pursue selling the land parcels as opposed to development. Due to the shortening of the expected period of ownership, the Company determined that it was necessary to reduce the carrying value of the land parcels to their estimated fair value and recorded land impairments charges of $24.6 million at December 31, 2018. As a result of its periodic evaluation of the recoverability of the carrying value, the Company recorded additional land impairment charges of $0.2 and $2.7 million in the three and nine months ended September 30, 2019, respectively.

Disclosure about fair value of assets and liabilities is based on pertinent information available to management as of September 30, 2019 and December 31, 2018. Although management is not aware of any factors that would significantly affect the fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since September 30, 2019 and current estimates of fair value may differ significantly from the amounts presented herein.