2. Basis of Presentation and Summary of Significant Accounting Policies

Boston Properties, Inc. does not have any other significant assets, liabilities or operations, other than its investment in the Operating Partnership, nor does it have employees of its own. The Operating Partnership, not Boston Properties, Inc., executes all significant business relationships. All majority-owned subsidiaries and affiliates over which the Company has financial and operating control and variable interest entities ("VIE"s) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company's share of the earnings of these joint ventures and companies is included in consolidated net income.

The accompanying interim financial statements are unaudited; however, the financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all of the disclosures required by accounting principles generally accepted in the United States of America for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair statement of the financial statements for these interim periods have been included. The results of operations for the interim periods are not necessarily indicative of the results to be obtained for other interim periods or for the full fiscal year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosure required by accounting principles generally accepted in the United States of America. These financial statements should be read in conjunction with the Company's financial statements and notes thereto contained in the Company's Annual Report in the Company's Form 10-K for its fiscal year ended December 31, 2011. Certain prior year amounts have been reclassified to conform to the current year presentation.

The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. The Company determines the fair value of its unsecured senior notes and unsecured exchangeable senior notes using market prices. The fair value of the Company's unsecured senior notes and unsecured exchangeable senior notes is categorized at a level 1 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company uses quoted market rates to value these instruments. The Company determines the fair value of its mortgage notes payable using discounted cash flow analyses by discounting the spread between the future contractual interest payments and hypothetical future interest payments on mortgage debt based on current market rates for similar securities. In determining the current market rates, the Company adds its estimates of market spreads to the quoted yields on federal government treasury securities with similar maturity dates to its debt. The fair value of the Company's mortgage notes payable is categorized at a level 3 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs.

Because the Company's valuations of its financial instruments are based on these types of estimates, the actual fair values of its financial instruments may differ materially if the Company's estimates do not prove to be accurate. The following table presents the aggregate carrying value of the Company's indebtedness and the Company's corresponding estimate of fair value as of March 31, 2012 and December 31, 2011 (in thousands):


	March 31, 2012					December 31, 2011
	Carrying Amount			Estimated Fair Value		Carrying Amount			Estimated Fair Value
Mortgage notes payable	$	2,946,760		$	3,060,477	$	3,123,267		$	3,297,903
Unsecured senior notes		3,865,369			4,185,434		3,865,186			4,148,461
Unsecured exchangeable senior notes		1,148,497	(1)		1,328,799		1,715,685	(1)		1,904,115

Total	$	7,960,626		$	8,574,710	$	8,704,138		$	9,350,479

(1)	Includes the net impact of Accounting Standards Codification ("ASC") ASC 470-20 totaling approximately $46.3 million and $54.5 million at March 31, 2012 and December 31, 2011, respectively.

Out-of-Period Adjustment

During the three months ended March 31, 2012, the Company recorded additional real estate operating expenses totaling approximately $3.2 million related to the cumulative non-cash straight-line adjustment to the ground rent expense of certain ground leases that were not previously recognized on a straight-line basis. This resulted in the overstatement of real estate operating expenses by approximately $3.2 million during the three months ended March 31, 2012 and in the understatement of real estate operating expenses in the aggregate amount of approximately $3.2 million in previous periods. Because this adjustment was not material to the prior years' consolidated financial statements and the impact of recording the adjustment in the current period is not material to the Company's consolidated financial statements, the Company recorded the related adjustment during the three months ended March 31, 2012.