LEXINGTON REALTY TRUST

(Exact name of registrant as specified in its charter)

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes x No ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ¨ No x

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x No ¨

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x No ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ¨ No x

The aggregate market value of the shares of beneficial interest, par value $0.0001 per share, classified as common stock (“common shares”) of Lexington Realty Trust held by non-affiliates as of June 29, 2018, which was the last business day of the registrant's most recently completed second fiscal quarter, was $2,044,256,426 based on the closing price of the common shares on the New York Stock Exchange as of that date, which was $8.73 per share.

Number of common shares outstanding as of March 8, 2019 was 235,282,784 .

DOCUMENTS INCORPORATED BY REFERENCE

Certain information contained in the Definitive Proxy Statement for Lexington Realty Trust's Annual Meeting of Shareholders, to be held on May 21, 2019, is incorporated by reference in this Annual Report on Form 10-K in response to Part III, Items 10, 11, 12, 13 and 14, which will be filed with the Securities and Exchange Commission not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K.

TABLE OF CONTENTS

Introduction

Unless stated otherwise or the context otherwise requires, the “Company,” the “Trust,” “Lexington,” “we,” “our,” and “us” refer collectively to Lexington Realty Trust and its consolidated subsidiaries. All of the Company's interests in properties are held, and all property operating activities are conducted, through special purpose entities, which we refer to as property owner subsidiaries or lender subsidiaries, which are separate and distinct legal entities, but in some instances are consolidated for financial statement purposes and/or disregarded for income tax purposes.

When we use the term “REIT,” we mean real estate investment trust. All references to 2018 , 2017 and 2016 refer to our fiscal years ended, or the dates, as the context requires, December 31, 2018 , December 31, 2017 and December 31, 2016 , respectively.

When we use the term “GAAP,” we mean United States generally accepted accounting principles in effect from time to time.

Cautionary Statements Concerning Forward-Looking Statements

This Annual Report, together with other statements and information publicly disseminated by us, contain certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995 and include this statement for purposes of complying with these safe harbor provisions. Forward-looking statements, which are based on certain assumptions and describe our future plans, strategies and expectations, are generally identifiable by use of the words “believes,” “expects,” “intends,” “anticipates,” “estimates,” “projects,” “may,” “plans,” “predicts,” “will,” “will likely result” or similar expressions. Readers should not rely on forward-looking statements since they involve known and unknown risks, uncertainties and other factors which are, in some cases, beyond our control and which could materially affect actual results, performances or achievements. In particular, among the factors that could cause actual results, performances or achievements to differ materially from current expectations, strategies or plans include, among others, those risks discussed below under “Risk Factors” in Part I, Item 1A of this Annual Report and under “Management's Discussion and Analysis of Financial Condition and Results of Operations” in Part II, Item 7 of this Annual Report. Except as required by law, we undertake no obligation to publicly release the results of any revisions to these forward-looking statements which may be made to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events. Accordingly, there is no assurance that our expectations will be realized.