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•	enhances investors' understanding of the General Partner and the Partnership by enabling investors to view the business as a whole in the same manner as management views and operates the business;

•	eliminates duplicative disclosure and provides a more streamlined and readable presentation of information since a substantial portion of the Company's disclosure applies to both the General Partner and the Partnership; and

•	creates time and cost efficiencies through the preparation of one combined report instead of two separate reports.

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•	Changes in general economic and business conditions, including the financial condition of our tenants and the value of our real estate assets;

•	The General Partner's continued qualification as a REIT for U.S. federal income tax purposes;

•	Heightened competition for tenants and potential decreases in property occupancy;

•	Potential changes in the financial markets and interest rates;

•	Volatility in the General Partner's stock price and trading volume;

•	Our continuing ability to raise funds on favorable terms;

•	Our ability to successfully identify, acquire, develop and/or manage properties on terms that are favorable to us;

•	Potential increases in real estate construction costs;

•	Our ability to successfully dispose of properties on terms that are favorable to us, including, without limitation, through one or more transactions that are consistent with our previously disclosed strategic plans;

•	Our ability to retain our current credit ratings;

•	Inherent risks in the real estate business, including, but not limited to, tenant defaults, potential liability relating to environmental matters and liquidity of real estate investments; and

•	Other risks and uncertainties described herein, as well as those risks and uncertainties discussed from time to time in our other reports and other public filings with the Securities and Exchange Commission ("SEC").

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•	We could become engaged in a dispute with any of our joint venture partners that might affect our ability to develop or operate a property;

•	Our joint venture partners may have different objectives than we have regarding the appropriate timing and terms of any sale or refinancing of properties;

•	Our joint venture partners may have competing interests in our markets that could create conflict of interest issues; and

•	Maturities of debt encumbering our jointly owned investments may not be able to be refinanced at all or on terms that are as favorable as the current terms.

•	Changes in the general economic climate;

•	The availability of capital on favorable terms, or at all;

•	Increases in interest rates;

•	Local conditions such as oversupply of property or a reduction in demand;

•	Competition for tenants;

•	Changes in market rental rates;

•	Delay or inability to collect rent from tenants who are bankrupt, insolvent or otherwise unwilling or unable to pay;

•	Difficulty in leasing or re-leasing space quickly or on favorable terms;

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•	Costs associated with periodically renovating, repairing and reletting rental space;

•	Our ability to provide adequate maintenance and insurance on our properties;

•	Our ability to control variable operating costs;

•	Changes in government regulations; and

•	Potential liability under, and changes in, environmental, zoning, tax and other laws.

•	Unsuccessful development opportunities could result in direct expenses to us;

•	Construction costs of a project may exceed original estimates, possibly making the project less profitable than originally estimated, or possibly unprofitable;

•	Time required to complete the construction of a project or to lease up the completed project may be greater than originally anticipated, thereby adversely affecting our cash flow and liquidity;

•	Occupancy rates and rents of a completed project may not be sufficient to make the project profitable; and

•	Favorable sources to fund our development activities may not be available.

•	Prices paid for acquired facilities are based upon a series of market judgments; and

•	Costs of any improvements required to bring an acquired facility up to standards to establish the market position intended for that facility might exceed budgeted costs.

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•	liabilities for clean-up of undisclosed environmental contamination;

•	claims by tenants, vendors or other persons against the former owners of the properties;

•	liabilities incurred in the ordinary course of business; and

•	claims for indemnification by general partners, directors, officers and others indemnified by the former owners of the properties.

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•	The General Partner would not be allowed a deduction for distributions to shareholders and would be subject to federal income tax (including any applicable alternative minimum tax) on its taxable income at regular corporate rates;

•	Unless the General Partner was entitled to relief under certain statutory provisions, it would be disqualified from treatment as a REIT for the four taxable years following the year during which it ceased to qualify as a REIT;

•	The General Partner's net earnings available for investment or distribution to its shareholders would decrease due to the additional tax liability for the year or years involved; and

•	The General Partner would no longer be required to make any distributions to shareholders in order to qualify as a REIT.

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•	The holders of 80% of the General Partner's outstanding shares of capital stock approve the transaction;

•	The transaction has been approved by three-fourths of those directors who served on the General Partner's board before the shareholder became a 10% owner; or

•	The significant shareholder complies with the "fair price" provisions of the General Partner's charter.

•	Any voluntary sale, exchange, merger, consolidation or other disposition of all or substantially all of the assets of the Partnership in one or more transactions other than a disposition occurring upon a financing or refinancing of the Partnership;

•	The General Partner's merger, consolidation or other business combination with another entity unless after the transaction substantially all of the assets of the surviving entity are contributed to the Partnership in exchange for Common Units;

•	The General Partner's assignment of its interests in the Partnership other than to one of its wholly-owned subsidiaries; and

•	Any reclassification or recapitalization or change of outstanding shares of the General Partner's common stock other than certain changes in par value, stock splits, stock dividends or combinations.

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(1)	Represents the average annual base rental payments, on a straight-line basis for the term of each lease, from space leased to tenants as of December 31, 2016, excluding additional amounts paid by tenants as reimbursement for operating expenses. Joint venture properties are shown at 100% of square feet and net effective rents, without regard to our ownership percentage.

(2)	Annual net effective rent per leased square foot.

(3)	Represents properties not located in our primary markets.

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•

Owned or jointly controlled 561 industrial, medical office and office properties, of which 534 properties totaling 130.2 million square feet were in service and 27 properties totaling 9.4 million square feet were under development. The 534 in-service properties were comprised of 492 consolidated properties totaling 119.5 million square feet and 42 jointly controlled properties totaling 10.7 million square feet. The 27 properties under development consisted of 25 consolidated properties with 8.4 million square feet and two jointly controlled properties with 1.0 million square feet.

•	Owned, including through ownership interests in unconsolidated joint ventures (with acreage not adjusted for our percentage ownership interest), 2,190 acres of land and controlled an additional 1,600 acres through purchase options.

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•	We generated $538.6 million of total net cash proceeds from the disposition of 32 consolidated buildings and 448 acres of wholly-owned undeveloped land.

•	We started new development projects with expected total costs of $697.2 million during 2016, which included $54.0 million of expected total costs for three development projects started within unconsolidated joint ventures. The development projects started in 2016 were mostly comprised of new industrial projects and were, in aggregate, 67.0% pre-leased.

•

In the fourth quarter of 2016, pursuant to a pre-existing purchase option, we acquired 14 properties in the Washington D.C. area from an unconsolidated joint venture (the "Quantico Joint Venture"). These 14 properties were comprised of 11 industrial buildings and three office properties. These 14 properties were previously encumbered by a $131.3 million CMBS loan and, pursuant to the terms of the purchase option, we repaid the loan as consideration for the acquisition of the underlying properties. One of the acquired office properties was sold immediately following the acquisition for $53.4 million, which was equal to the property's fair value.

•	During 2016, we placed 21 newly completed wholly-owned development projects in service, across all product types, which totaled 6.0 million square feet with total costs of $507.6 million. These properties were 94.9% leased at December 31, 2016.

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The total estimated cost of our consolidated properties under construction at December 31, 2016 totaled $713.1 million, with $338.6 million of such costs already incurred. The total estimated cost for jointly controlled properties under construction was $42.1 million at December 31, 2016, with $28.8 million of costs already incurred. The consolidated properties under construction are 74% pre-leased, while the jointly controlled properties under construction are 29% pre-leased.

•	Same-property net operating income, on a cash basis, as defined hereafter under "Supplemental Performance Measures" grew by 6.0% for the twelve months ended December 31, 2016, as compared to the same period in 2015.

•	The percentage of total square feet leased for our in-service portfolio of consolidated properties increased from 96.5% at December 31, 2015 to 97.2% at December 31, 2016.

•	Total leasing activity for our consolidated properties totaled 26.2 million square feet in 2016 compared to 19.4 million square feet in 2015. The increase in total leasing activity in 2016 was largely the result of leasing new development projects as well as a higher volume of lease renewals.

•	Total leasing activity for our consolidated properties in 2016 included 12.3 million square feet of renewals, which represented a 75.6% retention rate on a square foot basis, and resulted in a 13.7% increase in net effective rents.

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•	Throughout 2016, we issued 8.4 million shares of common stock pursuant to our at the market ("ATM") equity program at an average price of $25.93 per share, generating gross proceeds of $218.2 million and, after deducting commissions and other costs, net proceeds of $215.6 million.

•	In June 2016, we issued $375.0 million of senior unsecured notes that bear interest at a stated interest rate of 3.25%, an effective interest rate of 3.36%, and mature on June 30, 2026.

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During June and July 2016, we repaid $275.0 million of our 5.95% senior unsecured notes, which had a scheduled maturity of February 2017. Through a tender offer we repurchased $72.0 million of the notes and redeemed the remaining outstanding notes, for cash payments totaling $283.5 million. The repayment of these notes resulted in an $8.8 million loss on debt extinguishment, which included premiums paid to the holders of the notes as well as the write-off of unamortized deferred financing costs.

•	Throughout 2016, we repaid seven secured loans, totaling $346.7 million, which had a weighted average stated interest rate of 5.90%.

•	In October 2016, we redeemed $129.5 million of senior unsecured notes, which had a scheduled maturity in August of 2019, for a cash payment of $154.1 million. As the result of this redemption, we recognized a net loss on extinguishment totaling $25.2 million, which was comprised of premiums paid to the holders of the notes as well as the write-off of unamortized deferred financing costs.

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•	The sale of 123 properties since January 1, 2015, which did not meet the criteria for inclusion within discontinued operations, resulted in a $65.2 million decrease in rental and related revenue from continuing operations in the year ended December 31, 2016 when compared to 2015.

•	The acquisition of 19 properties and placing of 44 developments in service from January 1, 2015 to December 31, 2016 provided combined incremental revenues of $44.8 million in the year ended December 31, 2016 when compared to 2015.

•	Average commencement occupancy in the same property portfolio increased by 1.2% in the year ended December 31, 2016 when compared to 2015.

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•	The sale of 108 properties since January 1, 2014, which did not meet the criteria for inclusion within discontinued operations, resulted in a $77.1 million decrease in rental and related revenue from continuing operations in the year ended December 31, 2015 when compared to 2014.

•	We acquired seven properties, of which six were industrial and one was medical office, and placed 46 developments in service from January 1, 2014 to December 31, 2015. These acquisitions and developments provided combined incremental revenues of $48.2 million in the year ended December 31, 2015 when compared to 2014.

•	Average commencement occupancy in our same property portfolio increased by 1.6% in the year ended December 31, 2015 when compared to 2014.

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The value allocable to the above or below market component of an acquired in-place lease is determined based upon the present value (using a discount rate which reflects the risks associated with the acquired leases) of the difference between (i) the contractual amounts to be received pursuant to the lease over its remaining term and (ii) management's estimate of the amounts that would be received using fair market rates over the remaining term of the lease. The amounts allocated to above market leases are included in deferred leasing and other costs in the balance sheet and below market leases are included in other liabilities in the balance sheet; both are amortized to rental income over the remaining terms of the respective leases.

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Factors considered in determining the value allocable to in-place leases include estimates, during hypothetical lease up periods, related to space that is actually leased at the time of acquisition. These estimates include (i) lost rent at market rates, (ii) fixed operating costs that will be recovered from tenants and (iii) theoretical leasing commissions required to execute similar leases. These intangible assets are included in deferred leasing and other costs in the balance sheet and are amortized over the remaining term of the existing lease.

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•	Criteria for identifying and selecting our critical accounting policies;

•	Methodology in applying our critical accounting policies; and

•	Impact of the critical accounting policies on our financial statements.

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•	property investment;

•	leasing/capital costs;

•	dividends and distributions to shareholders and unitholders;

•	long-term debt maturities;

•	opportunistic repurchases of outstanding debt; and

•	other contractual obligations.

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•	Real estate development costs were $401.4 million, $370.5 million, and $446.7 million during 2016, 2015, and 2014, respectively. During 2016, we placed 21 newly completed wholly-owned development projects in service and expect to continue with a robust level of new development.

•	We paid cash of $269.8 million, $68.7 million and $193.4 million, respectively, for real estate and undeveloped land acquisitions during 2016, 2015 and 2014, respectively.

•	Sales of land and depreciated property generated net proceeds of $538.6 million, $1.68 billion and $493.2 million during 2016, 2015 and 2014, respectively.

•	Second generation tenant improvements, leasing costs and building improvements totaled $59.3 million, $61.9 million and $98.8 million during 2016, 2015 and 2014, respectively. The second generation capital

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•	During 2016, we also received a full repayment of a $200.0 million seller financed mortgage from the buyers of an office portfolio that we sold in April 2015.

•	We received capital distributions from unconsolidated companies as a result of the sale of properties or refinancing of $126.1 million, $69.0 million and $91.8 million during 2016, 2015 and 2014, respectively.

•	We made capital contributions and advances to unconsolidated companies in the amounts of $57.9 million, $72.4 million and $11.6 million during 2016, 2015 and 2014, respectively.

•	During 2016, the General Partner issued 8.4 million shares of common stock pursuant to its ATM equity programs for net proceeds of $215.6 million, compared to 233,000 shares of common stock for net proceeds of $4.5 million in 2015 and 16.4 million shares of common stock for net proceeds of $289.1 million in 2014.

•	In 2016, we issued $375.0 million of senior unsecured notes and in 2014 we issued $300.0 million of unsecured notes. We did not issue any unsecured notes in 2015.

•	During 2016, we repurchased or redeemed $404.5 million of unsecured notes, for cash payments totaling $437.6 million. During 2015, we repaid six unsecured notes, totaling $831.2 million, for cash payments totaling $910.9 million.

•	During 2016, we repaid seven secured loans, totaling $346.7 million. During 2015, we repaid 17 secured loans for cash payments totaling $231.2 million, which included early repayment premiums of $4.2 million for certain of the loans that were repaid prior to their scheduled maturity dates. During 2014, we repaid nine secured loans, totaling $99.3 million.

•	We decreased net borrowings on the Partnership's line of credit by $23.0 million in 2016, decreased net borrowings by $35.0 million in 2015 and increased net borrowings by $18.0 million in 2014.

•	We paid regular cash dividends or distributions of $0.73, $0.69 and $0.68 per common share or per Common Unit in each of the years ended December 31, 2016, 2015 and 2014, respectively.

•	In December 2015, we paid a one-time special dividend of $0.20 per share or per unit that was declared in order to maintain our compliance with the requirements for a REIT. The one-time special dividend was paid as a result of the significant taxable gains on asset sales completed in 2015.

•	Changes in book drafts are classified as financing activities within our consolidated Statements of Cash Flows. Book overdrafts were $13.4 million, $11.1 million and $7.8 million at December 31, 2016, 2015 and 2014, respectively.

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(1)

Our long-term debt consists of both secured and unsecured debt and includes both principal and interest. Interest payments for variable rate debt were calculated using the interest rates as of December 31, 2016. Repayment of our $250.0 million variable rate term note, which has a contractual maturity date in January 2019, is reflected as a 2020 obligation in the table above based on the ability to exercise a one-year extension, which we may exercise at our discretion.

(2)	Our unsecured line of credit has a contractual maturity date in January 2019, but is reflected as a 2020 obligation in the table above based on the ability to exercise a one-year extension, which we may exercise at our discretion. Interest payments for our unsecured line of credit were calculated using the most recent stated interest rate that was in effect.

(3)	Our share of unconsolidated joint venture debt includes both principal and interest. Interest expense for variable rate debt was calculated using the interest rate at December 31, 2016.

(4)	Represents estimated remaining costs on the completion of owned development projects and third-party construction projects.

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(a)	The following documents are filed as part of this Annual Report:

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(b)	Exhibits

(c)	Financial Statement Schedule

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•	Pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of assets of the company;

•	Provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and

•	Provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the company's assets that could have a material effect on the financial statements.

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•	Pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of assets of the Partnership;

•	Provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the General Partner; and

•	Provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the Partnership's assets that could have a material effect on the financial statements.

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(1)	The Company

(2)	Summary of Significant Accounting Policies

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(3)	Acquisitions and Dispositions

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(4)	Related Party Transactions

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(5)	Investments in Unconsolidated Companies

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(6)	Discontinued Operations, Assets Held-for-Sale and Impairments

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(7)	Indebtedness

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•	In 2016, we issued $375.0 million of unsecured notes that bear interest at a stated interest rate of 3.25%, have an effective interest rate of 3.36%, and mature on June 30, 2026.

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During June and July 2016 we repaid $275.0 million of our 5.95% senior unsecured notes, which had a scheduled maturity of February 2017, through the combination of a tender offer and the subsequent redemption of the remaining notes that were not tendered, for cash payments totaling $283.5 million. Together, the tender offer and the redemption resulted in an $8.8 million loss on debt extinguishment, which primarily consisted of premiums paid to the noteholders and the write-off of unamortized deferred financing costs.

•

In October 2016, we redeemed $129.5 million of unsecured notes, which had a scheduled maturity in August 2019, for a cash payment of $154.1 million. These notes had a stated rate of 8.25% and an effective rate of 8.38%. We recognized a net loss on the extinguishment of these notes in the fourth quarter totaling $25.2 million, which was comprised of a make-whole payment to the noteholders as well as the write-off of unamortized deferred financing costs.

•	In February 2015, we repaid a $250.0 million senior unsecured note at its maturity date. This loan had a stated interest rate of 7.38% and an effective rate of 7.50%.

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In April 2015, the Partnership completed a tender offer to purchase, for a combined aggregate purchase price (exclusive of accrued and unpaid interest) of up to $500.0 million, certain of its outstanding series of unsecured notes. A portion of the proceeds from the suburban office portfolio sale were used to fund the Tender Offer, which resulted in the repurchase of notes having a face value of $424.9 million, for a cash payment of $500.0 million. The repurchased notes had contractual maturity dates ranging between February 2017 and March 2020 and bore interest at stated rates ranging between 5.95% and 8.25%.

•	In May 2015, we repurchased unsecured notes with a face value of $6.3 million, for a cash payment of $7.1 million. These notes had a stated interest rate of 6.50% and an effective rate of 6.08%.

•	In October 2015, we redeemed $150.0 million in unsecured notes that had a scheduled maturity in March 2016, for a cash payment of $152.6 million. These notes had a stated interest rate of 5.50% and an effective rate of 6.72%.

•	During 2015, the early repayment of unsecured notes, either through the tender offer or repurchase, resulted in an aggregate loss on extinguishment of $82.0 million, which included applicable repurchase premiums as well as the write-off of unamortized deferred loan costs.

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(8)	Segment Reporting

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(9)	Leasing Activity

(10)	Employee Benefit Plans

(11)	Shareholders' Equity of the General Partner and Partners' Capital of the Partnership

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(12)	Stock Based Compensation

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(13)	Financial Instruments

(14)	Commitments and Contingencies

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(15)	Selected Interim Financial Information (unaudited)

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(16)	Subsequent Events

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(1)	The tax basis (in thousands) of our real estate assets at December 31, 2016 was approximately $6,769,583 (unaudited) for federal income tax purposes.

(2)	Depreciation of real estate is computed using the straight-line method over 40 years for buildings and 15 years for land improvements for properties that we develop, 30 years for buildings and 10 years for land improvements for properties that we acquire, and shorter periods based on lease terms (generally 3 to 10 years) for tenant improvements.

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