<PAGE>
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                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                            ------------------------

                                   FORM 10-Q

(MARK ONE)

<TABLE>
<C>        <S>
   /X/     QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 (D) OF THE
           SECURITIES EXCHANGE ACT OF 1934

           FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 1999
</TABLE>

                                       OR

<TABLE>
<C>        <S>
   / /     TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (D) OF THE
           SECURITIES EXCHANGE ACT OF 1934
           For the transition period from ------------ to ------------
</TABLE>

                        Commission file number 000-24905

                         BEACON CAPITAL PARTNERS, INC.

             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

<TABLE>
<CAPTION>
                 Maryland                                          04-3403281
                 --------                                          ----------
<S>                                                <C>
     (STATE OR OTHER JURISDICTION OF                   (IRS EMPLOYER IDENTIFICATION NO.)
      INCORPORATION OR ORGANIZATION)

     One Federal Street, 26th Floor,
          Boston, Massachusetts                                      02110
------------------------------------------         ------------------------------------------
 (ADDRESS OF PRINCIPAL EXECUTIVE OFFICE)                           (ZIP CODE)

                                        617-457-0400
---------------------------------------------------------------------------------------------
                    (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)
</TABLE>

    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 __

    Number of Common Shares outstanding at the latest practicable date,
November 15, 1999: 20,973,932 shares, $.01 par value.

--------------------------------------------------------------------------------
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<PAGE>
                         BEACON CAPITAL PARTNERS, INC.
                                   FORM 10-Q

                                     INDEX

<TABLE>
<CAPTION>
                                                                                  PAGE
                                                                                --------
<S>               <C>                                                           <C>
Part I --         Financial Information

  Item 1.         Consolidated Financial Statements...........................       1

                    Consolidated Balance Sheets--September 30, 1999
                      (Unaudited) and December 31, 1998.......................       1

                    Consolidated Statements of Operations--Three Months Ended
                      September 30, 1999 and 1998, Nine Months Ended
                      September 30, 1999 and the period from January 21, 1998
                      (Inception) to September 30, 1998 (Unaudited)...........       2

                    Consolidated Statements of Cash Flows--Nine Months Ended
                      September 30, 1999 and the period from January 21, 1998
                      (Inception) to September 30, 1998 (Unaudited)...........       3

                    Notes to Consolidated Financial Statements................       4

  Item 2.         Management's Discussion and Analysis of Financial Condition
                  and Results of Operations...................................       8

  Item 3.         Quantitative and Qualitative Disclosures about Market
                  Risk........................................................      16

Part II --        Other Information

  Item 1.         Legal Proceedings...........................................      17

  Item 2.         Changes in Securities and Use of Proceeds...................      17

  Item 3.         Defaults Upon Senior Securities.............................      17

  Item 4.         Submission of Matters to a Vote of Security Holders.........      17

  Item 5.         Other Information...........................................      17

  Item 6.         Exhibits and Reports on Form 8-K............................      17
</TABLE>
<PAGE>
PART I--FINANCIAL INFORMATION
  ITEM 1. CONSOLIDATED FINANCIAL STATEMENTS

                         BEACON CAPITAL PARTNERS, INC.

                          CONSOLIDATED BALANCE SHEETS

              (DOLLARS IN THOUSANDS, EXCEPT FOR PER SHARE AMOUNTS)

<TABLE>
<CAPTION>
                                                              SEPTEMBER 30,   DECEMBER 31,
                                                                  1999            1998
                                                              -------------   ------------
<S>                                                           <C>             <C>
                                                              (UNAUDITED)      (NOTE 1)
ASSETS
Real Estate:
  Land......................................................    $ 53,271        $ 51,094
  Buildings, improvements and equipment.....................     202,511         165,842
                                                                --------        --------
                                                                 255,782         216,936
  Less accumulated depreciation.............................       5,571           2,168
                                                                --------        --------
                                                                 250,211         214,768
Deferred financing and leasing costs, net of accumulated
  amortization of $702 and $42, respectively................       2,716             414
Cash and cash equivalents...................................      37,111         174,647
Restricted cash.............................................         797             697
Accounts receivable, net....................................       1,643           2,464
Accrued rent receivable.....................................         585             233
Other assets................................................       4,333             641
Investments in joint ventures and corporations..............     144,801          90,136
Other investment............................................      34,705              --
                                                                --------        --------
      Total assets..........................................    $476,902        $484,000
                                                                ========        ========
LIABILITIES AND STOCKHOLDERS' EQUITY
Liabilities:
  Mortgage notes payable....................................    $ 18,790        $ 21,570
  Note payable--interim financing...........................     100,000              --
  Accounts payable, accrued expenses and dividend payable...      10,498          18,731
                                                                --------        --------
      Total liabilities.....................................     129,288          40,301
                                                                --------        --------
Commitments and contingencies...............................          --              --
Minority interest in consolidated partnership...............      43,832          54,983
                                                                --------        --------
Stockholders' equity:
  Preferred stock; $.01 par value, 200,000,000 shares
    authorized, none issued or outstanding..................          --              --
  Excess stock; $.01 par value, 250,000,000 shares
    authorized, none issued or outstanding..................          --              --
  Common stock; $.01 par value, 500,000,000 shares
    authorized, 20,973,932 shares issued and outstanding....         210             210
  Additional paid-in capital................................     389,520         389,520
  Cumulative net income.....................................      15,224           9,054
  Cumulative dividends......................................    (101,172)        (10,068)
                                                                --------        --------
      Total stockholders' equity............................     303,782         388,716
                                                                --------        --------
      Total liabilities and stockholders' equity............    $476,902        $484,000
                                                                ========        ========
</TABLE>

                            SEE ACCOMPANYING NOTES.

                                       1
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

                     CONSOLIDATED STATEMENTS OF OPERATIONS

              (DOLLARS IN THOUSANDS, EXCEPT FOR PER SHARE AMOUNTS)

                                  (UNAUDITED)

<TABLE>
<CAPTION>
                                                                                       FOR THE PERIOD
                                          THREE MONTHS             NINE MONTHS        FROM JANUARY 21,
                                       ENDED SEPTEMBER 30,            ENDED          1998 (INCEPTION) TO
                                        1999         1998      SEPTEMBER 30, 1999    SEPTEMBER 30, 1998
                                     ----------   ----------   -------------------   -------------------
<S>                                  <C>          <C>          <C>                   <C>
Revenues:
  Rental income....................   $ 5,864      $ 5,274           $15,741               $ 5,435
  Reimbursement of operating
    expenses and real estate
    taxes..........................       253          735             1,844                   778
  Equity in earnings of joint
    venture........................     1,120        1,134             3,521                 2,087
  Interest and dividend income.....       629        2,756             5,413                 8,370
  Other income.....................       855          101             1,258                   125
                                      -------      -------           -------               -------
      Total revenues...............     8,721       10,000            27,777                16,795
                                      -------      -------           -------               -------
Expenses:
  Property operating...............     1,551        1,689             4,298                 1,702
  Real estate taxes................     1,210          946             3,509                   983
  General and administrative.......     2,281        2,954             7,204                 5,591
  Interest expense.................     1,203          446             1,670                   462
  Depreciation and amortization....     1,800        1,062             4,116                 1,119
                                      -------      -------           -------               -------
      Total expenses...............     8,045        7,097            20,797                 9,857
                                      -------      -------           -------               -------
Income before minority interest....       676        2,903             6,980                 6,938
Minority interest in consolidated
  partnership......................       (78)        (322)             (810)                 (389)
                                      -------      -------           -------               -------
      Net income...................   $   598      $ 2,581           $ 6,170               $ 6,549
                                      =======      =======           =======               =======
Income per common share--basic and
  diluted..........................   $  0.03      $  0.12           $  0.29               $  0.32
                                      =======      =======           =======               =======
Weighted average number of common
  shares outstanding (in
  thousands).......................    20,974       20,974            20,974                20,688
                                      =======      =======           =======               =======
</TABLE>

                            SEE ACCOMPANYING NOTES.

                                       2
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

                     CONSOLIDATED STATEMENTS OF CASH FLOWS

                             (DOLLARS IN THOUSANDS)

                                  (UNAUDITED)

<TABLE>
<CAPTION>
                                                                               FOR THE PERIOD
                                                                                    FROM
                                                                                JANUARY 21,
                                                               NINE MONTHS          1998
                                                                  ENDED        (INCEPTION) TO
                                                              SEPTEMBER 30,    SEPTEMBER 30,
                                                                   1999             1998
                                                              --------------   --------------
<S>                                                           <C>              <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
  Net income................................................    $   6,170        $   6,549
  Adjustments to reconcile net income to net cash provided
    by operating activities:
    Depreciation............................................        3,403            1,108
    Amortization............................................          713               11
    Equity in earnings of joint venture.....................       (3,521)          (2,087)
    Distribution from joint venture.........................        4,100               --
    Minority interest in consolidated partnership...........          810              389
  (Decrease) increase in cash arising from changes in
    operating assets and liabilities:
    Restricted cash.........................................         (100)              --
    Accounts receivable.....................................          821           (1,075)
    Accrued rent receivable.................................         (352)            (110)
    Other assets............................................       (2,534)            (625)
    Accounts payable and accrued expenses...................        3,156            6,227
                                                                ---------        ---------
      Net cash provided by operating activities.............       12,666           10,387
                                                                ---------        ---------
CASH FLOWS FROM INVESTING ACTIVITIES:
  Purchase of Wyndham preferred stock, net..................     (102,874)              --
  Real estate asset acquisitions and improvements...........      (38,846)        (142,628)
  Funding of mortgage note receivable.......................      (45,000)              --
  Repayment of mortgage note receivable.....................       45,000               --
  Other investment..........................................      (34,705)              --
  Payment of deferred leasing costs.........................         (938)            (266)
  Acquisition deposits and deferred costs...................       (1,158)             (38)
  Investments in joint ventures and corporations............      (55,244)         (68,888)
                                                                ---------        ---------
      Net cash used in investing activities.................     (233,765)        (211,820)
                                                                ---------        ---------
CASH FLOWS FROM FINANCING ACTIVITIES:
  Proceeds from note payable--interim financing.............      100,000               --
  Payment of deferred financing costs.......................       (2,077)            (103)
  Repayments on mortgage notes..............................       (2,780)             (91)
  Proceeds from loans payable--affiliate....................           --            3,560
  Repayment of loans payable--affiliate.....................           --           (3,560)
  Sale of Operating Partnership units.......................           --            4,228
  Sale of common stock......................................           --          417,871
  Offering costs............................................           --          (28,141)
  Distribution payment to minority interests................       (1,321)              --
  Dividend payment to stockholders..........................      (10,259)              --
                                                                ---------        ---------
      Net cash provided by financing activities.............       83,563          393,764
                                                                ---------        ---------

  Net (decrease) increase in cash and cash equivalents......     (137,536)         192,331
  Cash and cash equivalents, beginning of period............      174,647               --
                                                                ---------        ---------
  Cash and cash equivalents, end of period..................    $  37,111        $ 192,331
                                                                =========        =========
SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING AND FINANCING
  ACTIVITIES:
Issuance of Operating Partnership units to acquire
  property..................................................    $      --        $  51,359
Assumption of mortgage debt to acquire property.............           --           21,722
Cash paid for interest, net of capitalized interest of
  $1,272 and $0, respectively...............................        1,080              462
Distribution of Wyndham preferred stock to minority
  interests.................................................       11,961               --
Dividend of Wyndham preferred stock to stockholders.........       90,913               --
</TABLE>

                            SEE ACCOMPANYING NOTES.

                                       3
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

                               SEPTEMBER 30, 1999

              (DOLLARS IN THOUSANDS, EXCEPT FOR PER SHARE AMOUNTS)
                                  (UNAUDITED)

1. BASIS OF PRESENTATION

    The financial statements of Beacon Capital Partners, Inc. ("BCP") have been
prepared in accordance with generally accepted accounting principles for interim
financial information and with the instructions to Form 10-Q and Rule 10-01 of
Regulation S-X. Accordingly, they do not include all of the information and
footnotes required by generally accepted accounting principles for complete
financial statements. In the opinion of management, all adjustments (consisting
of normal recurring accruals) considered necessary for a fair presentation have
been included. Operating results for interim periods are not necessarily
indicative of the results that may be expected for the full year.

    The balance sheet at December 31, 1998 has been derived from the audited
financial statements at that date but does not include all of the information
and footnotes required by generally accepted accounting principles for complete
financial statements.

    For further information, refer to the consolidated financial statements and
footnotes thereto included in BCP's annual report on Form 10-K for the period
ended December 31, 1998.

2. ORGANIZATION

    Beacon Capital Partners, Inc. was incorporated on January 21, 1998 as a
Massachusetts corporation (the "Formation"), and was initially capitalized
through loans from the two founders of BCP, Messrs. Leventhal and Fortin. The
loans were repaid in May 1998. BCP qualifies as a real estate investment trust
under the Internal Revenue Code of 1986, as amended. BCP was established to
conduct real estate investment and development activities and currently operates
in one segment.

    On March 17, 1998, BCP was reincorporated as a Maryland corporation and on
March 20, 1998 it completed an initial private offering (the "Original
Offering") in accordance with Section 4(2) of the Securities Act of 1933. BCP
initially issued 17,360,769 common shares with proceeds, net of expenses, of
$323,110. In April, 1998, 3,613,163 additional shares were issued through the
exercise of the underwriter's over-allotment, with proceeds, net of expenses, of
$66,620.

    In connection with the reincorporation of BCP in Maryland, BCP established
Beacon Capital Partners, L.P. (the "Operating Partnership"). BCP and the
Operating Partnership are collectively referred to as the "Company". The
Operating Partnership is a Delaware limited partnership. BCP is the sole general
partner of, and, as of September 30, 1999, holds approximately 88% of the
economic interest in the Operating Partnership. BCP holds an approximate 1%
general partnership interest in the Operating Partnership and the balance is
held as a limited partnership interest. The limited partnership interests not
held by BCP are presented as minority interest in the accompanying consolidated
financial statements. The term of the Operating Partnership commenced on
March 16, 1998 and shall continue until January 1, 2056 or until such time as a
Liquidating Event, as defined, has occurred.

3. INVESTMENTS IN JOINT VENTURES AND CORPORATIONS

    The investments in joint ventures and corporations represents the Company's
interest in (i) a joint venture known as Beacon/PW Kendall LLC ("The Athenaeum
Portfolio"), (ii) a joint venture with Mathilda Partners LLC ("Mathilda Research
Centre"), (iii) a joint venture with HA L.L.C. ("Millennium Tower"), (iv) an
investment in preferred stock of Cypress Communications, Inc. ("Cypress"), and
(v) an investment in Series B Convertible Preferred Stock ("Series B Preferred")
of Wyndham International, Inc. ("Wyndham").

                                       4
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               SEPTEMBER 30, 1999

              (DOLLARS IN THOUSANDS, EXCEPT FOR PER SHARE AMOUNTS)
                                  (UNAUDITED)

3. INVESTMENTS IN JOINT VENTURES AND CORPORATIONS (CONTINUED)

    A reconciliation of the underlying net assets to the Company's carrying
value of investments in joint ventures and corporations is as follows:

<TABLE>
<CAPTION>
                                        THE      MATHILDA
                                     ATHENAEUM   RESEARCH   MILLENNIUM
                                     PORTFOLIO    CENTRE      TOWER      CYPRESS    WYNDHAM     TOTAL
                                     ---------   --------   ----------   --------   --------   --------
<S>                                  <C>         <C>        <C>          <C>        <C>        <C>
BCP, L.P. equity interest
  (including accumulated earnings,
  net of distributions)............   $63,213    $18,289     $ 9,423                           $ 90,925
Investments in preferred stock.....        --         --          --      $5,000    $47,041      52,041
Other costs........................        40        602         709          67        417       1,835
                                      -------    -------     -------      ------    -------    --------
Carrying value of investments in
  joint ventures and
  corporations.....................   $63,253    $18,891     $10,132      $5,067    $47,458    $144,801
                                      =======    =======     =======      ======    =======    ========
</TABLE>

THE ATHENAEUM PORTFOLIO

    Beacon/PW Kendall LLC was formed on April 16, 1998 and is jointly owned by
the Company and PW Acquisitions IX, LLC, an affiliate of PaineWebber. Initially
each member made a $5,000 contribution and the Company provided a loan to the
joint venture of approximately $117,000. The joint venture acquired The
Athenaeum Portfolio, an eleven building 970,000 square foot mixed-use portfolio
located in Cambridge, Massachusetts. In August 1998, the Company and PW
Acquisitions IX, LLC each made equity contributions of approximately $58,500,
which were used to repay the Company's loan receivable.

MATHILDA RESEARCH CENTRE

    On August 9, 1998, the Company entered into a joint venture agreement with
Mathilda Partners LLC, an affiliate of Menlo Equities, a California based
developer, to develop two four-story Class A office/R&D buildings with surface
parking in Sunnyvale, California, known as Mathilda Research Centre. The Company
and Mathilda Partners LLC have agreed to fund 87.5% and 12.5% of the equity
required, respectively. On November 4, 1998, the joint venture acquired a
twelve-acre site on Mathilda Avenue in Sunnyvale, CA, on which it is developing
the project. The estimated cost of the 267,000 square foot development is
approximately $64,000. The joint venture has obtained a $44,000 construction
loan from an institutional lender to finance the development, and the balance of
the development costs will be funded by equity contributions from the venturers.

MILLENNIUM TOWER

    On September 1, 1998 the Company entered into a joint venture agreement with
HA L.L.C., an affiliate of Martin Smith Real Estate Services, a Seattle based
real estate company, to develop a high-rise building in downtown Seattle,
Washington, known as Millennium Tower. The Company and HA L.L.C. have agreed to
fund 66 2/3% and 33 1/3% of the equity required, respectively. Land has been
contributed to the joint venture by HA L.L.C. at an agreed value of $10,500, and
the Company has agreed to fund the first $19,000 of cash requirements for the
venture. The joint venture has obtained a $45,000 construction loan from two
institutional lenders to finance the balance of the development costs. The
estimated cost of the project is $72,000, including the value of the land.

                                       5
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               SEPTEMBER 30, 1999

              (DOLLARS IN THOUSANDS, EXCEPT FOR PER SHARE AMOUNTS)
                                  (UNAUDITED)

3. INVESTMENTS IN JOINT VENTURES AND CORPORATIONS (CONTINUED)

CYPRESS

    On September 30, 1998, the Company invested $5,000 to acquire preferred
stock in Cypress, at that time representing a 13.5% fully diluted ownership
position in Cypress. On October 8, 1999, Cypress raised additional capital, at
which time the Company invested $6,000 to acquire additional preferred stock. As
a result of the additional equity raised, the Company now holds a 9.7% fully
diluted ownership position. Dividends will be earned on the Company's investment
as and when dividends are declared on the preferred stock or any other class of
stock in Cypress. The preferred stock will be treated preferentially upon a
liquidation of Cypress, should a liquidation occur, and is held by both the
Operating Partnership and Tenant Communications, Inc., a Massachusetts
corporation ("Tenant Communications"). The voting common stock of Tenant
Communications is controlled by Messrs. Leventhal and Fortin. The Operating
Partnership owns 99% of the economic interests in Tenant Communications.

WYNDHAM

    On June 30, 1999, the Company purchased 1,050,000 shares of Series B
Preferred of Wyndham at a net price of approximately $102,874. Simultaneously
with this transaction, the Company transferred all of these shares of Series B
Preferred to a voting trust (the "Voting Trust") (the trustee of which is a
subsidiary of the Operating Partnership) and declared and paid a dividend of
approximately $4.34 per share of common stock of BCP and a distribution of
approximately $4.34 per operating partnership unit of the Operating Partnership.
The aggregate value of the dividend and distribution was approximately $103,064
and primarily consisted of the Company's interest in shares of the Series B
Preferred. Stockholders not able to receive such interests received cash of
equivalent value. In August, 1999, the Company purchased an aggregate of
approximately 30,480 units of the Voting Trust at a price of approximately
$2,986. On November 2, 1999, the Company purchased approximately 18,036 units of
the Voting Trust at a price of approximately $1,737.

    On July 1, 1999, the Company purchased 450,000 shares of Series B Preferred
at a net price of approximately $44,055. On October 29, 1999, the Company
transferred 244,340 of these shares of Series B Preferred to Beacon Lodging,
Inc., a Massachusetts corporation ("Beacon Lodging"). The voting common stock of
Beacon Lodging is controlled by Messrs. Leventhal and Fortin. The Operating
Partnership owns 99% of the economic interests in Beacon Lodging. Wyndham has a
right to redeem up to 450,000 shares of the Series B Preferred that the Company
has purchased, depending upon the results of a rights offering to current
Wyndham common shareholders. Depending upon the timing and magnitude of
Wyndham's rights offering, the Company may establish a second voting trust to
hold some or all of the 450,000 shares of Series B Preferred.

4. OTHER INVESTMENTS

215 FREMONT STREET

    On June 30, 1999, the Company invested $33,500, exclusive of closing and
redevelopment costs, in 215 Fremont Street, a 299,000 square foot building
located in the South Financial District of San Francisco, California. On
October 25, 1999, this investment was transferred to an affiliate of the
Company, Beacon Capital Strategic Partners, L.P., a newly formed real estate
limited partnership, the initial closing of which

                                       6
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               SEPTEMBER 30, 1999

              (DOLLARS IN THOUSANDS, EXCEPT FOR PER SHARE AMOUNTS)
                                  (UNAUDITED)

4. OTHER INVESTMENTS (CONTINUED)

occurred on October 1, 1999. The Company was reimbursed for all costs associated
with the acquisition and redevelopment of the property.

MORTGAGE NOTE RECEIVABLE--PAH BATTERYMARCH REALTY COMPANY, LLC

    On May 21, 1999 and June 25, 1999, the Company funded mortgage note advances
of approximately $12,300 and $32,700, respectively (net of interest and fees) to
PAH Batterymarch Realty Company, LLC, an entity wholly owned by Patriot American
Hospitality Partnership, L.P., for the development of the Wyndham Batterymarch
Hotel located in Boston, Massachusetts. The mortgage note was collateralized by
a first mortgage lien on the property and was guaranteed by Wyndham and Patriot
American Hospitality Partnership, L.P. The mortgage note had an interest rate of
LIBOR plus 250 basis points and was repaid on July 1, 1999.

5. MORTGAGE NOTES PAYABLE

    The mortgage notes payable, collateralized by certain properties and
assignments of leases, total $18,790 at September 30, 1999. The mortgage notes
payable have fixed interest rates ranging from 7.75% to 9.25% and maturities
ranging from May 2002 to October 2022. The net book value of the mortgaged
assets is $52,304 at September 30, 1999.

    Future minimum principal payments due during the next five years and
thereafter are as follows:

<TABLE>
        <S>                                                           <C>
        1999........................................................  $    88
        2000........................................................      373
        2001........................................................      404
        2002........................................................    1,815
        2003........................................................      414
        Thereafter..................................................   15,696
                                                                      -------
        Total                                                         $18,790
                                                                      =======
</TABLE>

6. NOTE PAYABLE--INTERIM FINANCING

    On June 28, 1999, the Company obtained $100,000 of secured interim financing
(the "Interim Financing") from Bankers Trust Company. The Interim Financing
matures in June 2000, but in certain circumstances can be extended for one year.
Outstanding balances under the Interim Financing bear interest at a rate spread
over the base rate or Eurodollar rate, as applicable. The spread is based upon
certain loan to value ratios. At September 30, 1999, the outstanding balance of
the Interim Financing was $100,000 and the interest rate was 8.16%. The Interim
Financing requires monthly payments of interest only and is secured by mortgages
and assignments of rents on certain properties. The net book value of the
collateralized assets is $125,931 at September 30, 1999.

    The Company's ability to borrow under the Interim Financing is subject to
the Company's ongoing compliance with a number of financial and other covenants.

                                       7
<PAGE>
ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
  OF OPERATIONS.

OVERVIEW

    This Form 10-Q contains forward-looking statements within the meaning of
Section 27A of the Securities Act of 1933 and Section 21E of the Securities
Exchange Act of 1934. The words "believe", "expect", "anticipate", "intend",
"estimate" and other expressions which are predictions of or indicate future
events and trends and which do not relate to historical matters identify
forward-looking statements. Our actual results could differ materially from
those set forth in the forward-looking statements. Certain factors that might
cause such a difference include the following: real estate investment
considerations, such as the effect of economic and other conditions in the
market area on cash flows and values; the ability to obtain third party
shareholder approval for investment transactions; the need to renew leases or
relet space upon the expiration of current leases, and the ability of a property
to generate revenue sufficient to meet debt service payments and other operating
expenses; risks associated with borrowing, such as the possibility that we will
not have sufficient funds available to make principal payments on outstanding
debt and outstanding debt may be refinanced at higher interest rates or
otherwise on terms less favorable to the Company; the impact of pending or
future litigation; variations in quarterly operating results; the risk that we
and our third party property managers, tenants or vendors may experience
unanticipated delays or expenses in achieving Year 2000 compliance; securities
held for investment are subject to fluctuations in valuation based upon the
performance of the underlying business and those risks and uncertainties
contained elsewhere in this report and under the heading "Risk Factors" of our
Registration Statement on Form S-11 as filed with the Securities and Exchange
Commission on June 16, 1998, as subsequently amended.

    The following discussion and analysis of the financial condition and results
of operations should be read in conjunction with the accompanying consolidated
financial statements and notes thereto. Our consolidated financial statements
include Beacon Capital Partners, Inc. ("BCP") and Beacon Capital Partners, L.P.
(the "Operating Partnership"), our majority-owned partnership.

RESULTS OF OPERATIONS

COMPARISON OF THE NINE MONTHS ENDED SEPTEMBER 30, 1999 AND THE PERIOD FROM
JANUARY 21, 1998 (INCEPTION) TO SEPTEMBER 30, 1998 AND THE THREE MONTHS ENDED
SEPTEMBER 30, 1999 AND SEPTEMBER 30, 1998.

    Our total revenues increased $11.0 million to $27.8 million for the nine
months ended September 30, 1999 as compared to $16.8 million for the period from
January 21, 1998 (Inception) to September 30, 1998. The increase was due to Fort
Point Place, Technology Square, The Draper Building and the Dallas Office and
Industrial Portfolio acquisitions rental income and reimbursement of operating
expenses and real estate taxes of $10.3 million and $1.1 million, respectively,
The Athenaeum Portfolio equity earnings of $1.4 million and other income of
$1.2 million offset by a decrease in interest and dividend income of
$3.0 million. Revenues for The Athenaeum Portfolio were $22.6 million and
expenses were $15.6 million for the nine months ended September 30, 1999; we
recognize 50% of its net earnings. The $3.0 million decrease in interest and
dividend income was primarily the result of a reduction in investment cash on
hand due to our use of the March, 1998 Offering Proceeds to fund property
acquisitions and investments, offset by the interest earned on the mortgage note
receivable and dividends received in 1999.

    Our total expenses increased $10.9 million to $20.8 million for the nine
months ended September 30, 1999 as compared to $9.9 million for the period from
January 21, 1998 (Inception) to September 30, 1998. The increase was due to Fort
Point Place, Technology Square, The Draper Building and the Dallas Office and
Industrial Portfolio acquisitions property operating expenses, real estate taxes
and interest expense of $2.6 million, $2.5 million and $1.2 million,
respectively, additional general and administrative expenses of $1.6 million and
depreciation and amortization expense of $3.0 million.

                                       8
<PAGE>
    Our total revenues decreased $1.3 million for the three months ended
September 30, 1999 as compared to the three months ended September 30, 1998. The
decrease was due to decreases in reimbursement of operating expenses and real
estate taxes and interest and dividend income of $.5 million and $2.1 million,
respectively, offset by increases in rental income and other income of
$.6 million and $.7 million, respectively. The $.5 million decrease in
reimbursement of operating expenses and real estate taxes was primarily the
result of Polaroid vacating and the new leases at Technology Square with current
operating and real estate tax bases. The $2.1 million decrease in interest and
dividend income was primarily the result of a reduction in investment cash on
hand due to our use of the March, 1998 Offering Proceeds to fund property
acquisitions and investments. The $.6 million increase in rental income was
primarily the result of the acquisition of Fort Point Place and releasing at
545 Technology Square. Additional leases executed at Technology Square have rent
commencement dates subsequent to September 30, 1999. The $.7 million increase in
other income was primarily the result of reimbursements from 215 Fremont
St.--See Investing Activities.

    Our total expenses increased $.9 million for the three months ended
September 30, 1999 as compared to the three months ended September 30, 1998. The
increase was due to increases in real estate taxes, interest expense, and
depreciation and amortization expense of $.3 million, $.7 million, and
$.7 million, respectively offset by decreases in property operating expenses and
general and administrative expenses of $.1 million and $.7 million,
respectively. The $.3 million increase in real estate taxes was primarily the
result of the Fort Point Place acquisition. The $.7 million increase in interest
expense was primarily the result of interest related to the Bankers Trust
Company interim financing obtained in June, 1999. The $.7 million increase in
depreciation and amortization expense was primarily the result of the Fort Point
Place acquisition depreciation and the amortization of Bankers Trust Company
interim financing fees. The $.1 million decrease in property operating expenses
was primarily the result of the Technology Square redevelopment buildings taken
out of service in 1999 offset by Fort Point Place acquisition property operating
expenses. The $.7 million decrease in general and administrative expenses was
primarily the result of the write-off of due diligence costs incurred in 1998
for projects not acquired.

    The minority interest in consolidated partnership represents the portion of
the Operating Partnership that is not owned by the Company.

LIQUIDITY AND CAPITAL RESOURCES

    Cash and cash equivalents were $37.1 million at September 30, 1999 as
compared to $174.6 million at December 31, 1998. The decrease of $137.5 million
was primarily the result of (i) the purchase of Series B Convertible Preferred
Stock ("Series B Preferred") of Wyndham International, Inc. ("Wyndham"),
(ii) the funding of the mortgage note to PAH Batterymarch Realty Company, LLC,
(iii) the investment in 215 Fremont Street, (iv) the payment of the
January 1999 dividend to stockholders and distribution to minority interests,
(v) the acquisition of Fort Point Place, (vi) the payment of Technology Square
redevelopment costs and (vii) investments in Mathilda Research Centre and
Millennium Tower, all offset by (i) proceeds received from the Bankers Trust
Company interim financing note payable (the "Interim Financing"), (ii) the
repayment of the mortgage note by PAH Batterymarch Realty Company, LLC and
(iii) cash flow from operations.

SHORT AND LONG-TERM LIQUIDITY

    We have considered our short-term (up to 12 months) liquidity needs and the
adequacy of expected liquidity sources to meet these needs. We believe that our
principal short-term operating liquidity needs are to fund normal recurring
expenses, debt service requirements and the minimum distribution required to
maintain the Company's REIT qualification under the Internal Revenue Code of
1986, as amended. We believe that these needs will be funded from cash flow
provided by operating activities and the dividend to shareholders of those
shares of Series B Preferred of Wyndham subject to the voting trust. See "--
Investing Activities". We believe our short-term investment liquidity needs are
to fund current real estate

                                       9
<PAGE>
investments, developments and redevelopments, as well as securities held for
investment. We expect to fund these needs from cash on hand and through
mortgages and other debt instruments.

    We expect to meet long-term (greater than 12 months) liquidity requirements
for the costs of additional development, real estate and real estate related
investments, scheduled debt maturities, major renovations, expansions and other
non-recurring capital improvements through secured and unsecured indebtedness,
joint ventures, sale of certain assets, the issuance of additional Operating
Partnership units and equity securities and from current cash balances.

INVESTING ACTIVITIES

    On August 9, 1998, we entered into a joint venture agreement with Mathilda
Partners LLC, an affiliate of Menlo Equities (a California based developer). The
joint venture is developing Mathilda Research Centre, two four-story Class A
office/R&D buildings with surface parking in Sunnyvale, California. We agreed to
fund up to $19.8 million of the development, of which, as of September 30, 1999,
we had funded approximately $18.3 million using proceeds from the Original
Offering. In conjunction with the construction loan closing, our equity
investment was reduced to $17.5 million. See "--Financing Activities". On
June 18, 1999, the joint venture executed a lease with Juniper Networks, Inc.
for one of the two buildings comprising approximately 144,000 of the
development's approximately 267,000 square feet; the tenant also has an option
to lease the other building.

    On September 1, 1998 we entered into a joint venture agreement with HA
L.L.C., an affiliate of Martin Smith Real Estate Services (a Seattle based real
estate company). The joint venture is developing Millennium Tower, a 19-story
office and residential tower, in downtown Seattle, Washington. We agreed to fund
$19 million of the development, of which, as of September 30, 1999, we had
funded approximately $9.4 million using proceeds from the Original Offering.

    On May 21, 1999 and June 25, 1999 we funded mortgage note advances of
approximately $12.3 million and $32.7 million, respectively (net of interest and
fees) to PAH Batterymarch Realty Company, LLC, an entity wholly owned by Patriot
American Hospitality Partnership, L.P. for the development of the Wyndham
Batterymarch Hotel located in Boston, Massachusetts. The mortgage note was
collateralized by a first mortgage lien on the property and was guaranteed by
Wyndham and Patriot American Hospitality Partnership, L.P. We used proceeds from
the Original Offering for the advances. The mortgage note had an interest rate
of LIBOR plus 250 basis points and was repaid on July 1, 1999.

    On June 30, 1999, we invested $33.5 million, exclusive of closing and
redevelopment costs, in 215 Fremont Street, a 299,000 square foot building
located in the South Financial District of San Francisco, California. We used
proceeds from the Interim Financing for the investment. On October 25, 1999,
this investment was transferred to one of our affiliates, Beacon Capital
Strategic Partners, L.P., a newly formed real estate limited partnership, the
initial closing of which occurred on October 1, 1999. We were reimbursed for all
costs associated with the acquisition and redevelopment of the property.

    On June 30, 1999, we purchased 1,050,000 shares of Series B Preferred of
Wyndham at a net price of approximately $102.9 million. Simultaneously with this
transaction, we transferred all of these shares of Series B Preferred to a
voting trust (the "Voting Trust") (the trustee of which is a subsidiary of the
Operating Partnership) and declared and paid a dividend of approximately $4.34
per share of common stock of BCP and a distribution of approximately $4.34 per
operating partnership unit of the Operating Partnership. The aggregate value of
the dividend and distribution was approximately $103.1 million and primarily
consisted of our interest in shares of the Series B Preferred. Stockholders not
able to receive such interests received cash of equivalent value. We used
proceeds from the Original Offering for the Series B Preferred purchase. In
August, 1999, we purchased an aggregate of approximately 30,480 units of the
Voting Trust at a price of approximately $3.0 million. On November 2, 1999, we
purchased approximately 18,036 units of the Voting Trust at a price of
approximately $1.7 million. We used proceeds from the Interim Financing for the
purchase of the Voting Trust units.

                                       10
<PAGE>
    On July 1, 1999, we purchased 450,000 shares of Series B Preferred at a net
price of approximately $44.1 million. We used proceeds from the Original
Offering for the Series B Preferred purchase. On October 29, 1999, we
transferred 244,340 of these shares of Series B Preferred to Beacon Lodging,
Inc., a Massachusetts corporation ("Beacon Lodging"). The voting common stock of
Beacon Lodging is controlled by Messrs. Leventhal and Fortin. We own 99% of the
economic interests in Beacon Lodging. Wyndham has a right to redeem up to
450,000 shares of the Series B Preferred that we have purchased, depending upon
the results of a rights offering to current Wyndham common shareholders.
Depending upon the timing and magnitude of Wyndham's rights offering, we may
establish a second voting trust to hold some or all of the 450,000 shares of
Series B Preferred.

    On July 13, 1999, we purchased Fort Point Place, a four-building, 335,000
square foot office and warehouse property located in the Boston, Massachusetts
South Boston Waterfront District for aggregate consideration of approximately
$24.3 million. Two buildings consist of approximately 145,000 square feet of
office space. The other two buildings consist of approximately 190,000 square
feet of warehouse space which were delivered to us vacant. We intend to renovate
the warehouse space for use as residential condominiums. We used proceeds from
the Interim Financing for the acquisition.

    On October 1, 1999, we completed the initial closing for Beacon Capital
Strategic Partners, L.P., a real estate limited partnership, of which BCP
Strategic Partners LLC, our wholly-owned subsidiary, is the General Partner. The
initial equity commitment of $130 million includes investments from various
endowments, foundations and other institutional investors. The fund will
continue to accept capital commitments from additional limited partners for an
interim time period and currently expects to meet its funding target of
$250 million. We have committed to invest 20 percent of the total capital raised
with a minimum investment of $50 million. Beacon Capital Strategic Partners,
L.P. will be our exclusive real estate investment vehicle for a two-year period.
The fund will invest in U.S. domestic real estate with a primary focus on office
properties. The strategy will include redevelopment, development and other
opportunities where we can maximize value through our operating skills and
expertise.

    On October 8, 1999, we invested $6 million to acquire additional preferred
stock in Cypress Communications, Inc. ("Cypress"). Including this investment, we
hold a 9.7% diluted ownership position in Cypress. We used proceeds from the
Interim Financing for the investment.

    On November 12, 1999, we invested $8 million in Co Space, Inc., a company
that provides co-location space for data storage, telecommunication carriers,
and web-hosting applications. This investment represents a 19% ownership
position on a fully diluted basis. We used proceeds from the Interim Financing
for the investment.

FINANCING ACTIVITIES

    On June 9, 1999, Millennium Tower, L.L.C., the joint venture formed to
develop Millennium Tower, obtained a three-year $45 million construction loan
from two institutions. The loan may be extended for one year if certain
conditions are met. The loan initially bears interest at a rate of LIBOR plus
250 basis points and may decrease to a rate of LIBOR plus 200 basis points when
the project achieves certain pre-leasing and debt service coverage thresholds.
The loan is secured by a mortgage and an assignment of rents. Each of the
principals in the venture has provided a completion guarantee and a repayment
guarantee (in the aggregate amount of $12 million) equal to their pro-rata
interest in the venture.

    On June 28, 1999, we obtained $100 million of secured Interim Financing. The
Interim Financing matures in June 2000, but in certain circumstances can be
extended for one year. Outstanding balances under the Interim Financing bear
interest at a rate spread over the base rate or Eurodollar rate, as applicable.
The spread is based upon certain loan to value ratios. At September 30, 1999,
the outstanding balance of the Interim Financing was $100 million and the
interest rate was 8.16%. The Interim Financing requires monthly payments of
interest only and is secured by mortgages and assignments of rents on

                                       11
<PAGE>
certain properties. Our ability to borrow under the Interim Financing is subject
to our ongoing compliance with a number of financial and other covenants.

    On October 6, 1999, we obtained a 30 month $16 million loan from an
institutional lender secured by Fort Point Place. The loan may be extended for
one year if certain conditions are met. The lender has currently disbursed
$12.5 million of the loan and the balance will be available when the project
achieves certain leasing and debt service coverage thresholds. The loan bears
interest at a rate of LIBOR plus 200 basis points and requires monthly payments
of interest only.

    On October 29, 1999, Mathilda Associates LLC, the joint venture formed to
develop Mathilda Research Centre, obtained a three-year $44 million construction
loan from an institutional lender. As the construction of the two buildings at
Mathilda Research Centre will be phased, the lender's obligation to make
disbursements for the second building ($17 million) is subject to the project's
satisfaction of certain conditions. The loan initially bears interest at a rate
of LIBOR plus 275 basis points and may decrease to a rate of LIBOR plus 250
basis points when the first building is complete and Juniper Networks takes
occupancy. The Operating Partnership has provided a completion guarantee.

CAPITALIZATION

    As of September 30, 1999, our total consolidated debt was approximately
$118.8 million, and our total consolidated debt plus our proportionate share of
total unconsolidated debt was approximately $153.0 million. Our current
consolidated indebtedness has a weighted average rate of 8.15% (8.12% on fixed
rate debt and 8.16% on variable rate debt), with maturities ranging from 2000
through 2022, and is secured by some of our properties. Our proportionate share
of the current total unconsolidated mortgage debt on The Athenaeum Portfolio (in
which we hold a 50% interest in the limited liability company that controls the
two limited liability companies that hold title to this portfolio) is
approximately $34.2 million with a rate of 8.485%. It has a stated maturity of
2027 and may be prepaid any time after January 2007. Prior to January, 2007 but
after April, 1999, all or a portion of the loan may be defeased. In the event
the loan is not paid in full in 2007, the interest rate changes to the greater
of 13.485% or 5% over the applicable 20-year Treasury Rate. Our total
consolidated and unconsolidated debt has a weighted average rate of 8.23% as of
September 30, 1999.

    The following table, which includes both consolidated and unconsolidated
debt, summarizes the scheduled amortization of principal and maturities of the
loans outstanding.

<TABLE>
<CAPTION>
                                                          SCHEDULED
                                                         AMORTIZATION   MATURITIES     TOTAL
                                                         ------------   ----------   ----------
                                                                 (DOLLARS IN THOUSANDS)
<S>                                                      <C>            <C>          <C>
October 1, 1999 -- December 31, 1999...................     $  158                    $    158
2000...................................................        650       $100,000      100,650
2001...................................................        714             --          714
2002...................................................        727          1,426        2,153
2003...................................................        782             --          782
Thereafter.............................................      5,387         43,155       48,542
                                                            ------       --------     --------
    Total..............................................     $8,418       $144,581     $152,999
                                                            ======       ========     ========
</TABLE>

FUNDS FROM OPERATIONS

    We believe that to facilitate a clear understanding of the operating results
of the Company, Funds from Operations ("FFO") should be examined in conjunction
with net income. The definition of FFO was clarified in the National Association
of Real Estate Investment Trusts, Inc. ("NAREIT") White Paper, adopted by the
NAREIT Board of Governors in March 1995, as net income (loss) (computed in
accordance with generally accepted accounting principles), excluding gains
(losses) from debt restructuring and sales of properties, plus real estate
related depreciation and amortization, and after adjustments for

                                       12
<PAGE>
unconsolidated partnerships and joint ventures. Adjustments for unconsolidated
partnerships and joint ventures will be calculated to reflect FFO on the same
basis. FFO should not be considered as a substitute for net income, as an
indication of our performance, as a substitute for cash flow or as a measure of
our liquidity. The following table presents the calculations of FFO:

<TABLE>
<CAPTION>
                                                                                        FOR THE
                                                                                      PERIOD FROM
                                                                                   JANUARY 21, 1998
                                                                    NINE              (INCEPTION)
                                                                MONTHS ENDED       TO SEPTEMBER 30,
                                                             SEPTEMBER 30, 1999          1998
                                                             -------------------   -----------------
                                                                (UNAUDITED, DOLLARS IN THOUSANDS)
<S>                                                          <C>                   <C>
Income before extraordinary items and before minority
  interest in consolidated partnership.....................
                                                                   $ 6,980              $ 6,938
Add real estate related depreciation and amortization:
  Consolidated entities....................................          3,438                1,080
  Joint venture entities...................................          1,549                  936
                                                                   -------              -------
Funds from operations before minority interest.............         11,967                8,954
Company share of consolidated partnership..................          88.40%               94.39%
                                                                   -------              -------
Company funds from operations..............................        $10,579              $ 8,452
                                                                   =======              =======
Weighted average number of common shares outstanding (in
  thousands)...............................................         20,974               20,668
                                                                   =======              =======
</TABLE>

                                       13
<PAGE>
PROPERTY INFORMATION

    The following chart sets forth the occupancy rate, expressed as a
percentage, the average annual Base Rent (as defined below) and the average Net
Effective Rent (as defined below) per square foot for each of our properties as
of September 30, 1999. Base Rent is gross rent excluding payments by tenants on
account of real estate tax and operating expense escalation charges. Net
Effective Rent is Base Rent adjusted on a straight-line basis for contractual
rent step-ups and free rent periods, plus tenant payments on account of real
estate tax and operating expense escalation charges, less total operating
expenses and real estate taxes.

<TABLE>
<CAPTION>
                                                                                     AVERAGE    AVERAGE
                                                                TOTAL        %         BASE     NET EFF
PROPERTY                                                        AREA       LEASED      RENT       RENT
--------                                                      ---------   --------   --------   --------
<S>                                                           <C>         <C>        <C>        <C>
SOUTH BOSTON, MA:
Fort Point Place (1)........................................    145,222      97%      $15.49     $ 9.11
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average South Boston, MA..............    145,222      97%       15.49       9.11
                                                              ---------     ---       ------     ------
CAMBRIDGE, MA:
215 First Street (2)........................................    306,084     100%       20.17      15.08
One Kendall Square Cinema (2)...............................     31,641     100%       18.29      13.48
Buildings 100--500 (2)......................................    222,372     100%       26.68      20.05
Buildings 600/650/700 (2)...................................    236,661      97%       34.22      25.02
Buildings 1500 & 1700 (2)...................................     39,707      90%       16.07      11.56
Building 1400 (2)...........................................    133,211     100%       30.48      21.51
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average...............................    969,676      99%       26.27      19.33
                                                              ---------     ---       ------     ------
545 Technology Square (3)...................................    156,270      96%       32.33      23.98
549 Technology Square (4)...................................     40,377      35%       14.29      14.29
565 Technology Square (3)...................................    203,600      51%       35.00      27.86
575 Technology Square (3 & 5)...............................    182,250      59%       37.92      29.77
The Draper Building (NNN) (2)...............................    474,817     100%        6.16       6.16
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average...............................  1,057,314      80%       18.45      15.08
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average Cambridge, MA.................  2,026,990      89%       22.60      17.33
                                                              ---------     ---       ------     ------
SUBURBAN DALLAS, TX:
OFFICE
Bank One LBJ................................................     42,000      73%       13.61       7.59
Brandywine Place............................................     66,237      90%       12.59       9.55
Crosspoint Atrium...........................................    220,212      85%       13.49       7.60
Forest Abrams Place.........................................     68,827      99%       13.65       7.80
6500 Greenville Avenue......................................    114,600      90%       13.62       7.38
Northcreek Place II.........................................    163,303      88%       15.05       8.68
One Glen Lakes..............................................    166,272      90%       16.45      11.74
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average...............................    841,451      88%       14.35       8.79
                                                              ---------     ---       ------     ------
R&D / INDUSTRIAL
Park North Business Center..................................     36,885      92%        5.82       4.80
Plaza at Walnut Hill........................................     88,280      88%        7.47       4.62
Richardson Business Center..................................     66,300     100%        4.42       4.27
Richardson Commerce Centre..................................     60,517      79%        7.17       5.57
Sherman Tech................................................     16,176     100%        7.17       5.23
T I Business Park...........................................     96,902      89%        6.42       5.34
Venture Drive Tech Center...................................    128,322      85%        4.56       3.28
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average...............................    493,382      89%        5.90       4.51
                                                              ---------     ---       ------     ------
  Subtotal / Weighted Average Suburban Dallas, TX...........  1,334,833      88%       11.22       7.20
                                                              ---------     ---       ------     ------
  Total / Weighted Average Properties.......................  3,507,045      89%      $17.99     $13.15
                                                              =========     ===       ======     ======
</TABLE>

----------------------------------

(1) Fort Point Place includes two additional buildings that are not included in
    these figures. The two buildings consist of approximately 190,000 square
    feet of vacant warehouse space. We intend to renovate the warehouse space
    for use as residential condominiums.

(2) Currently being offered for sale, see "Recent Developments"

(3) The rentable areas of 545, 565 and 575 Technology Square have been modified
    to reflect recent re-measurements according to BOMA standards. 565 and 575
    Technology Square are currently undergoing substantial renovation and
    releasing programs.

(4) The building is occupied on a temporary basis and is expected to be
    demolished as part of the overall development plan.

(5) The 575 Technology Square information represents a signed lease for a tenant
    due to occupy their space in January 2000.

                                       14
<PAGE>
    The following table sets forth Lease Expirations (in square feet) for the
portfolio of properties the Company owned or had an interest in as of September
30, 1999.

<TABLE>
<CAPTION>
                                             SQUARE     % OF SQUARE    ANNUAL    % ANNUAL      # OF
                                            FEET (1)     FEET (2)     RENT (3)   RENT (4)   TENANTS (5)
                                            ---------   -----------   --------   --------   -----------
<S>                                         <C>         <C>           <C>        <C>        <C>
10/1/99--12/31/99.........................     87,948        2.5%     $ 1,116       1.8%         42
2000......................................    431,945       12.3%       6,623      10.8%         88
2001......................................    802,755       22.9%      10,068      16.4%         74
2002......................................    453,465       12.9%       8,884      14.5%         82
2003......................................    455,626       13.0%       8,348      13.6%         58
Thereafter................................    896,381       25.6%      26,292      42.9%         65
                                            ---------      -----      -------     -----         ---
  Total...................................  3,128,120       89.2%     $61,331     100.0%        409
                                            =========      =====      =======     =====         ===
</TABLE>

------------------------

(1) Total area in square feet covered by such leases.

(2) Percentage of total square feet of company portfolio.

(3) Annualized expiring base rental income represented by such leases in the
    year of expiration plus the current tenant payments on account of operating
    expense and real estate tax escalation charges.

(4) Calculated as annual rent divided by the total annual rent.

(5) The number of tenants whose leases will expire.

RECENT DEVELOPMENTS

    In April of 1999, we announced that we have offered for sale a portfolio of
properties located in Cambridge, Massachusetts. See -- "Property Information."
The portfolio, known as The Cambridge Technology Portfolio, consists of the
entire Athenaeum Portfolio and The Draper Building. The offering price is
approximately $286 million.

YEAR 2000 READINESS DISCLOSURE

    The Year 2000 compliance issue concerns the inability of computer systems to
accurately calculate, store or use a date after 1999. The inability of a
computer to properly process dates after 1999 could result in system failures or
miscalculations. Such failures in our computers could lead to disruptions in our
activities and operations. If we fail, or our significant tenants or vendors
fail, to make necessary modifications and conversions on a timely basis to
remedy these problems, the Year 2000 issue could have a material adverse effect
on us and our results of operations or financial position. We believe that our
competitors face similar risks in regard to Year 2000.

    We are managing our Year 2000 initiative to minimize any adverse effect on
our business operations. We have established a Year 2000 committee to address
Year 2000 concerns. The Year 2000 committee has implemented a Year 2000
initiative with the following phases: (i) introducing Year 2000 awareness;
(ii) identifying our systems with potential Year 2000 issues; (iii) assessing
and budgeting Year 2000 compliance costs; (iv) remediation; (v) testing;
(vi) contacting third party managers and material vendors to assess their Year
2000 compliance; and (vii) developing a contingency plan in case our Year 2000
initiative is not successful.

    We have completed phases (i), (ii), (iii), (iv) and (v) of our Year 2000
initiative. We have reviewed our corporate computer operations that consist of
recent releases of network systems, accounting, property management and desktop
applications. All such systems were installed in 1998 and we have contacted the
vendors of these systems for assurance that the systems are Year 2000 compliant.
All corporate hardware and software have been upgraded to meet the vendor's
specifications in regards to Year 2000 compliance.

                                       15
<PAGE>
All corporate and property financial records are maintained on our corporate
accounting system which is Year 2000 compliant. Although the testing of these
systems has been successfully completed, we will continue to test hardware and
software through December 31, 1999.

    We are in the final stage of phase (vi) of our Year 2000 initiative.
Included in the contractual obligations of the third party managers who operate
our properties is an undertaking to work with us on our Year 2000 initiative.
The third party managers are responsible for resolving Year 2000 issues with
respect to the building systems and the systems of the properties' tenants and
vendors. Over the last year, our Year 2000 committee has had regular
communications with our third party managers concerning Year 2000 compliance. We
are anticipating the third party manager's final completion statement by mid
November.

    We have the right to approve all lease agreements and have reviewed our
standard lease form to address Year 2000 compliance issues.

    The inability of the Company, or our tenants or vendors, to be Year 2000
compliant could lead to declining occupancy rates, higher operating expenses and
other adverse effects which are not quantifiable at this time. The failure of
any of these parties to be Year 2000 compliant could have a material adverse
effect on our results of operations or financial position.

    We have not incurred any material costs to address Year 2000 compliance. We
do not currently expect that future costs, if any, incurred in connection with
the initiative will have a material adverse impact on our results of operations
or financial position.

    In the unlikely event that we do not successfully address the Year 2000
issues, we have developed a contingency plan for our operations. The plan
includes the use of a "hot site" that would enable us to mirror our existing
environment to continue daily corporate and property financial operations. We
believe that we have substantially completed our Year 2000 initiative and will
continue to address any hardware and software changes that may adversely effect
our systems.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

    We are exposed to certain financial market risks, the most predominant being
fluctuations in interest rates. Interest rate fluctuations are monitored by
management as an integral part of our overall risk management program, which
recognizes the unpredictability of financial markets and seeks to reduce the
potentially adverse effect on our results of operations. The effect of interest
rate fluctuations historically has been small relative to other factors
affecting operating results, such as rental rates and occupancy.

    The following table summarizes our debt obligations outstanding as of
September 30, 1999. This information should be read in conjunction with Notes 5
and 6 to the consolidated financial statements.

<TABLE>
<CAPTION>
                                                          EXPECTED MATURITY DATE
                         10/1/99-
                         12/31/99     2000       2001       2002       2003     THEREAFTER    TOTAL     FAIR VALUE
                         --------   --------   --------   --------   --------   ----------   --------   ----------
                                                          (DOLLARS IN THOUSANDS)
<S>                      <C>        <C>        <C>        <C>        <C>        <C>          <C>        <C>
Liabilities
LONG-TERM DEBT:
-----------------------
FIXED RATE.............   $   88    $    373     $404      $1,815      $414       $15,696    $ 18,790    $ 18,790
Weighted Average Fixed
  Interest Rate........     8.1%        8.1%     8.1%        8.0%      8.0%          8.6%        8.2%

VARIABLE RATE..........       --    $100,000       --          --        --            --    $100,000    $100,000
Current Variable
  Interest Rate........       --       8.16%       --          --        --            --       8.16%
</TABLE>

                                       16
<PAGE>
                         BEACON CAPITAL PARTNERS, INC.

PART II -- OTHER INFORMATION

Item 1.  Legal Proceedings

    On August 20, 1999 an action was filed in the Massachusetts Superior Court
of Suffolk County by The Gillette Company against the Company, the City of
Boston Zoning Board of Appeals and others in which Gillette is appealing the
zoning approvals obtained by the Company to convert two vacant warehouse
buildings into residential condominiums at the Fort Point Place property located
in the South Boston Waterfront District. The Company intends to vigorously
defend itself and to seek to uphold the zoning approvals previously obtained.

Item 2.  Changes in Securities and Use of Proceeds

    None.

Item 3.  Defaults upon Senior Securities

    None.

Item 4.  Submission of Matters to a Vote of Security Holders

    None.

Item 5.  Other Information

    None.

Item 6.  Exhibits and Reports on Form 8-K

<TABLE>
        <S>  <C>     <C>
        (a)   3.1    Articles of Incorporation.(1)
              3.2    Certificate of Correction to Articles of Incorporation.(1)
              3.3    Amended and Restated By-laws.(1)
              3.4    Agreement of Limited Partnership of Beacon Capital Partners,
                       L.P.(2)
              3.5    First Amendment to Agreement of Limited Partnership.(2)
             10.1    Employment and Non-Competition Agreement for Alan M.
                       Leventhal.(1)
             10.2    Employment and Non-Competition Agreement for Lionel P.
                       Fortin.(1)
             10.3    Beacon Capital Partners 1998 Stock Option and Incentive
                       Plan.(1)
             10.4    Form of Indemnification Agreement between the Registrant and
                       its directors and executive officers.(1)
             10.5    Purchase and Sale Contract between Eastern Properties Master
                       LLC and the Registrant.(1)
             10.6    Contract of Sale for Bank One Building.(2)
             10.7    Contract of Sale for 6500 Greenville Building.(2)
             10.8    Contract of Sale for North Creek II Building.(2)
             10.9    Contract of Sale for One Glen Lakes Building.(2)
             10.10   Contract of Sale for Crosspoint Atrium Building.(2)
             10.11   Contract of Sale for Brandywine Place Building.(2)
             10.12   Contract of Sale for Forest Abrams Building.(2)
             10.13   Contract of Sale for Sherman Tech Building.(2)
             10.14   Contract of Sale for Venture Tech Building.(2)
             10.15   Contract of Sale for Plaza at Walnut Building.(2)
             10.16   Contract of Sale for Richardson BC Building.(2)
             10.17   Contract of Sale for Park North SC Building.(2)
             10.18   Contract of Sale for TI Business Center.(2)
             10.19   Contract of Sale for Richardson CC Building.(2)
             10.20   Contribution Agreement by and between Luddite Associates and
                       Beacon Capital Partners, L.P.(3)
             10.21   Credit Agreement with Bankers Trust Company.(4)
             10.22   Securities Purchase Agreement by and among Patriot American
                       Hospitality, Inc., Wyndham International, Inc., Beacon
                       Capital Partners, L.P. and the remaining parties named
                       therein.(5)
             10.23   Amendment to Securities Purchase Agreement by and among
                       Patriot American Hospitality, Inc., Wyndham International,
                       Inc., Beacon Capital Partners, L.P. and the remaining
                       parties named therein.(6)
</TABLE>

                                       17
<PAGE>
<TABLE>
        <S>  <C>     <C>
             27.     Financial Data Schedule.
</TABLE>

<TABLE>
        <S>  <C>     <C>
        (b)  Current report on Form 8-K filed on July 1, 1999.
             Current report on Form 8-K filed on September 13, 1999.
</TABLE>

--------------------------

(1) Previously filed as an exhibit to the Company's Registration Statement on
    Form S-11 (SEC File No. 333-56937) filed with the Commission on June 16,
    1998.

(2) Previously filed as an exhibit to Pre-Effective Amendment No. 1 to the
    Company's Registration Statement on Form S-11 (SEC File No. 333-56937) filed
    with the Commission on August 21, 1998.

(3) Previously filed as an exhibit to Post-Effective Amendment No. 3 to the
    Company's Registration Statement on Form S-11 (SEC File No. 333-56937) filed
    with the Commission on March 29, 1999.

(4) Previously filed as an exhibit to the Company's quarterly report on
    Form 10-Q filed with the Commission on August 16, 1999.

(5) Incorporated by reference to the joint Current Report on Form 8-K filed by
    Wyndham International, Inc. and Patriot American Hospitality, Inc. on
    March 2, 1999.

(6) Incorporated by reference to the Current Report on Form 8-K filed by Wyndham
    International, Inc. on July 13, 1999.

                                       18
<PAGE>
                                   SIGNATURES

    Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

<TABLE>
<S>                                                   <C>
                                                      BEACON CAPITAL PARTNERS, INC.

                                                      /s/ RANDY J. PARKER
                                                      ------------------------------------------------
                                                      Randy J. Parker
                                                      Chief Financial Officer (Authorized Officer and
November 15, 1999                                     Principal Accounting Officer)
</TABLE>