Exhibit
4.1


CORPORATE
OFFICE PROPERTIES TRUST


ARTICLES SUPPLEMENTARY

ESTABLISHING AND FIXING THE RIGHTS AND PREFERENCES

OF

SERIES K CUMULATIVE REDEEMABLE CONVERTIBLE PREFERRED SHARES

(PAR VALUE $0.01 PER SHARE)


CORPORATE
OFFICE PROPERTIES TRUST, a Maryland real estate investment
trust (hereinafter called the “Trust”), having its principal office in
Columbia, Maryland, hereby certifies to the State Department of Assessments and
Taxation of the State of Maryland that:


FIRST:
Pursuant to authority expressly vested in the Board of Trustees of the Trust by
Article VI of the Declaration of Trust of the Trust, as amended to date and as
the same may be amended hereafter from time to time (the “Declaration of Trust”),
and in accordance with Section 2-208(b) of the Maryland General Corporation
Law, the Board of Trustees has duly classified 600,000 authorized but unissued
preferred shares of beneficial interest of the Trust (the “Preferred Shares”)
into a series designated as 5.60% Series K Cumulative Redeemable Convertible
Preferred Shares, par value $0.01 per share, and has provided for the issuance
of such class by adoption of a resolution in the form of Article Third hereof
effective as of January 8, 2007.


SECOND: The classification
increases the number of shares classified as 5.60% Series K Cumulative
Redeemable Convertible Preferred Shares, par value $0.01 per share, from no
shares immediately prior to the classification to 600,000 shares immediately
after the classification.  The
classification decreases the number of unclassified Preferred Shares from
4,660,000 to 4,060,000.


THIRD:
The terms of the 5.60% Series K Cumulative Redeemable Convertible Preferred
Shares (including the preferences, conversion and other rights, voting powers,
restrictions, limitations as to dividends and other distributions,
qualifications, or terms or conditions of redemption) as set by the Board of
Trustees are as follows:


1.                                      NUMBER
OF SHARES AND DESIGNATION.


This series of
Preferred Shares shall be designated as 5.60% Series K Cumulative Redeemable
Convertible Preferred Shares, par value $0.01 per share (the “Series K
Preferred Shares”), and 600,000 shares shall be the authorized number of such
Series K Preferred Shares constituting such series.  The designations, powers, preferences and relative
participating, optional or other special rights, and the qualifications,
limitations or restrictions, of the Series K Preferred Shares shall be subject
in all cases to the provisions of Article VII of the Declaration of Trust
regarding limitations on beneficial ownership of the Trust’s equity securities.


2.                                      DEFINITIONS.


 











For purposes of
the Series K Preferred Shares, the following terms shall have the meanings
indicated:


“Affiliate” of a
Person means a Person that directly, or indirectly through one or more
intermediaries, controls or is controlled by, or is under common control with,
the Person specified.


“Board of Trustees” shall mean the Board of Trustees
of the Trust or any committee authorized by such Board of Trustees to perform
any of its responsibilities with respect to the Series K Preferred Shares; provided,
that for purposes of Section 8(a) of this Article, the term “Board of Trustees”
shall not include any such committee.


“Business Day” shall mean any day other than a
Saturday, Sunday or a day on which state or federally chartered banking
institutions in New York, New York are not required to be open.


“Code” shall mean the Internal Revenue Code of 1986,
as amended from time to time, or any successor statute thereto.  Reference to any provision of the Code shall
mean such provision as in effect from time to time, as the same may be amended,
and any successor thereto, as interpreted by any applicable regulations or
other administrative pronouncements as in effect from time to time.


“Common Shares”
shall mean the common shares of beneficial interest, par value $0.01 per share,
of the Trust.


“Calculation Price” shall have the meaning set forth in
the Purchase Agreement.


“Current Market Price” of publicly traded Common Shares
or any other class or series of capital shares or other security of the Trust
or of any similar security of any other issuer for any day shall mean the last
reported sales price, regular way settlement on such day, or, if no sale takes
place on such day, the average of the reported closing bid and asked prices
regular way on such day, in either case as reported on the New York Stock
Exchange (“NYSE”) or, if such security is not listed or admitted for trading on
the NYSE, on the principal national securities exchange on which such security
is listed or admitted for trading or, if not listed or admitted for trading on
any national securities exchange, the average of the closing bid and asked
prices on such day in the over-the-counter market as reported by the NASDAQ
Stock Market, Inc. (“NASDAQ”) or, if bid and asked prices for such security on
such day shall not have been reported through NASDAQ, the average of the bid
and asked prices on such day as furnished by any NYSE member firm regularly
making a market in such security selected for such purpose by the Chief
Executive Officer of the Trust or the Trustees or if any class or series of
securities are not publicly traded, the fair value of the shares of such class
as determined reasonably and in good faith by the Trustees.


“Declaration of
Trust” shall mean the Amended and Restated Declaration of Trust of the Trust as
filed for record with the State Department of Assessments and Taxation of the
State of Maryland, and any amendments thereto.



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“Dividend Payment
Date” shall mean January 15, April 15, July 15 and October 15 of each year; provided,
that if any Dividend Payment Date falls on any day other than a Business Day,
the dividend payment payable on such Dividend Payment Date shall be paid on the
Business Day immediately following such Dividend Payment Date and no interest
shall accrue on such dividend from such date to such Dividend Payment Date.


“Dividend Periods”
shall mean the Initial Dividend Period and each subsequent quarterly dividend
period commencing on and including January 15, April 15, July 15 and October 15
of each year and ending on and including the day preceding the first day of the
next succeeding Dividend Period, other than the Dividend Period during which
any Series K Preferred Shares shall be redeemed pursuant to Section 5 of this Article, which shall end on and
include the Redemption Date with respect to the Series K Preferred Shares being
redeemed.


“Dividend Record
Date” shall have the meaning set forth in Section 3(a) of this Article.


“Equity Shares”
shall mean shares of any class or series of shares of beneficial ownership in
the Trust.


“Exchange Act”
shall mean the Securities Exchange Act of 1934, as amended.


“Initial Dividend
Period” shall mean the period commencing on and including the Issue Date and
ending on and including April 14, 2007.


“Issue Date” shall
mean January 9, 2007.


“Junior Shares”
shall have the meaning set forth in Section 8(a) of this Article.


“Liquidation
Preference” shall have the meaning set forth in Section 4(a) of this Article.


“Operating
Partnership” shall mean Corporate Office Properties, L.P., a Delaware limited
partnership.


“Parity Shares”
shall have the meaning set forth in Section 8(b) of this Article.


“Person” shall
mean an individual, corporation, partnership, estate, trust (including a trust
qualifying under Section 401(a) or 501(c)(17) of the Code), a portion of a
trust permanently set aside for or to be used exclusively for the purposes
described in Section 642(c) of the Code, association, “private foundation,”
within the meaning of Section 509(a) of the Code, joint stock company or other
entity, and also includes a “group,” as that term is used for purposes of
Section 13(d)(3) of the Exchange Act, and a group to which an Excepted Holder
Limit (as defined in Article VII of the Declaration of Trust) applies.


“Purchase
Agreement” shall mean that certain Purchase Agreement and Agreement and Plan of
Merger, dated as of December 21, 2006, by and among the Trust, the Operating



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Partnership, W&M
Business Trust, a Maryland business trust and Nottingham Village, Inc., a
Maryland corporation.


“Redemption Date”
shall mean, in the case of any redemption of any Series K Preferred Shares, the
date fixed for redemption of such shares.


“Redemption Notice”
shall have the meaning set forth in Section 5(e) of this Article.


“Redemption Price”
shall mean, with respect to any Series K Preferred Shares to be redeemed, a
cash payment equal to 100% of the Liquidation Preference thereof plus all
accrued and unpaid dividends, if any, to the Redemption Date.


“REIT” shall mean
a “real estate investment trust,” as defined in Section 856 of the Code.


“Senior Shares”
shall have the meaning set forth in Section 7(c) of this Article.


“Series G
Preferred Shares” shall mean the Trust’s 8% Series G Cumulative Redeemable
Preferred Shares of beneficial interest, par value $0.01 per share.


“Series H
Preferred Shares” shall mean the Trust’s 7.5% Series H Cumulative Redeemable
Preferred Shares of beneficial interest, par value $0.01 per share.


“Series J
Preferred Shares” shall mean the Trust’s 7.625% Series E Cumulative Redeemable
Preferred Shares of beneficial interest, par value $0.01 per share.


“Set apart for
payment” shall be deemed to include, without any action other than the
following, the recording by the Trust in its accounting ledgers of any
accounting or bookkeeping entry which indicates, pursuant to a declaration of
dividends or other distribution by the Board of Trustees, the allocation of
funds to be so paid on any series or class of Equity Shares of the Trust; provided,
that the funds are actually available for and have been segregated for such
purpose; provided, further, that if any funds for any class or
series of Junior Shares or any class or series of Parity Shares are placed in a
separate account of the Trust or delivered to a disbursing, paying or other
similar agent, then “set apart for payment” with respect to the Series K
Preferred Shares shall mean placing such funds in a separate account or
delivering such funds to a disbursing, paying or other similar agent.


“Transfer Agent”
means Wells Fargo & Company or such transfer agent as may be designated
from time to time by the Board of Trustees or its designee as the transfer
agent for the Series K Preferred Shares.


“Trustee” shall
mean a member of the Board of Trustees.


“Voting Parity Shares” shall have the meaning set
forth in Section 8(a) of this Article.



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3.                                      DIVIDENDS.


(a)                                  The
holders of Series K Preferred Shares shall be entitled to receive, when, as and
if declared by the Board of Trustees, out of funds legally available for the
payment of dividends, quarterly cash dividends on the Series K Preferred Shares
at the rate of 5.60% of the Liquidation Preference per year ($2.80 per share
per year).  Such dividends shall accrue
and be cumulative from the Issue Date, whether or not in any Dividend Period or
Periods such dividends shall be declared or there shall be funds of the Trust
legally available for the payment of such dividends, and shall be payable
quarterly in arrears on each Dividend Payment Date, commencing on April 15,
2007.  Each such dividend shall be
payable in arrears to the holders of record of the Series K Preferred Shares,
as they appear on the share records of the Trust at the close of business on
the applicable record date (the “Dividend Record Date”), which shall be
fixed by the Board of Trustees and which shall be not more than 60 days nor
less than 10 days prior to each such Dividend Payment Date.  The Dividend Record Date for the dividend
payable on April 15, 2007 shall be March 31, 2007.  Accrued and unpaid dividends for any past
Dividend Periods may be declared and paid at any time, without reference to any
regular Dividend Payment Date, to holders of record on such date, which date
shall not precede by more than 45 days nor less than 15 days the payment date
thereof, as may be fixed by the Board of Trustees.


(b)                                 Any
dividend payable on the Series K Preferred Shares for any partial Dividend
Period shall be computed ratably on the basis of twelve 30-day months and a
360-day year.  Holders of Series K
Preferred Shares shall not be entitled to any dividends in excess of full
cumulative dividends, as herein provided, on the Series K Preferred
Shares.  No interest, or sum of money in
lieu of interest, shall be payable in respect of any dividend payment or
payments on the Series K Preferred Shares that may be in arrears.


(c)                                  So
long as any of the Series K Preferred Shares are outstanding, when dividends
are not paid in full upon the Series K Preferred Shares or any other
class or series of Parity Shares, or a sum sufficient for such payment is not
set apart for payment, all dividends declared upon the Series K Preferred
Shares and any Parity Shares shall be declared ratably in proportion to the
respective amounts of dividends accrued and unpaid on the Series K Preferred
Shares and accrued and unpaid on such Parity Shares.  Except as set forth in the preceding
sentence, unless dividends on the Series K Preferred Shares equal to the full
amount of accrued and unpaid dividends have been or contemporaneously are
declared and paid or declared and a sum sufficient for the payment thereof has
been or contemporaneously is set apart for such payment, for all past dividends
periods, no dividends shall be declared or paid or set apart for payment by the
Trust and no other distribution of cash or other property may be declared or
made, directly or indirectly, by the Trust with respect to any Parity Shares.


(d)                                 So
long as any of the Series K Preferred Shares are outstanding, unless dividends
equal to the full amount of all accrued and unpaid dividends on the Series K
Preferred Shares have been paid, or declared and set apart for payment, for all
past dividend periods, no dividends (other than dividends or distributions paid
in Junior Shares or options, warrants or rights to subscribe for or purchase
Junior Shares) may be declared or paid or set apart for payment by the Trust
and no other distribution of cash or other property may be declared or made,
directly or indirectly, by the Trust with respect to any Junior Shares, nor
shall any Junior Shares be



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redeemed, purchased or
otherwise acquired (except for a redemption, purchase or other acquisition of
Common Shares made for purposes of an employee incentive or benefit plan of the
Trust or a subsidiary of the Trust) for any consideration (or any monies be
paid to or made available for a sinking fund for the redemption of any such
Junior Shares), directly or indirectly, by the Trust (except by conversion into
or exchange for Junior Shares, or options, warrants or rights to subscribe for
or purchase Junior Shares), nor shall any other cash or other property be paid
or distributed to or for the benefit of holders of Junior Shares.


(e)                                  Notwithstanding
the provisions of this Section 3, the Trust shall not be prohibited from (i)
declaring or paying or setting apart for payment any dividend or distribution
on any Parity Shares or (ii) redeeming, purchasing or otherwise acquiring any
Parity Shares, in each case, if such declaration, payment, redemption, purchase
or other acquisition is necessary in order to maintain the continued
qualification of the Trust as a REIT under Section 856 of the Code.


4.                                      LIQUIDATION
PREFERENCE.


(a)                                  Upon
any voluntary or involuntary liquidation, dissolution or winding-up of the
Trust, before any payment or distribution by the Trust shall be made to or set
apart for payment to the holders of any Junior Shares, the holders of Series K
Preferred Shares shall be entitled to receive a liquidation preference of fifty
dollars ($50.00) per Series K Preferred Share (the “Liquidation Preference”),
plus an amount equal to all accrued and unpaid dividends (whether or not earned
or declared) to the date of final distribution to such holders; but such
holders shall not be entitled to any further payment.  Until the holders of the Series K Preferred
Shares have been paid the Liquidation Preference in full, plus an amount equal
to all accrued and unpaid dividends (whether or not earned or declared) to the
date of final distribution to such holders, no payment will be made to any
holder of Junior Shares upon the liquidation, dissolution or winding-up of the
Trust.  If, upon any liquidation,
dissolution or winding-up of the Trust, the assets of the Trust, or proceeds
thereof, distributable among the holders of Series K Preferred Shares shall be
insufficient to pay in full the Liquidation Preference and liquidating payments
on any other shares of any class or series of Parity Shares, then such assets,
or the proceeds thereof, shall be distributed among the holders of Series K Preferred
Shares and any such other Parity Shares ratably in the same proportion as the
respective amounts that would be payable on such Series K Preferred Shares and
any such other Parity Shares if all amounts payable thereon were paid in full.  For the purposes of this Section 4, a
voluntary or involuntary liquidation, dissolution or winding-up of the Trust
shall not include (i) a consolidation or merger of the Trust with or into one
or more other entities, (ii) a sale or transfer of all or substantially all of
the Trust’s assets, or (iii) a statutory share exchange.


(b)                                 Upon
any liquidation, dissolution or winding-up of the Trust, after payment shall
have been made in full to the holders of Series K Preferred Shares and any
Parity Shares, as provided in Section 4(a) of this Article, any other series or
class or classes of Junior Shares shall, subject to the respective terms
thereof, be entitled to receive any and all assets remaining to be paid or
distributed, and the holders of the Series K Preferred Shares and any Parity
Shares shall not be entitled to share therein.



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5.                                      REDEMPTION


(a)                                  Except
as set forth in Section 5(b) of this Article below or as set forth in Article
VII of the Declaration of Trust that is incorporated by reference herein
(relating to share ownership limitations in order to preserve REIT status), the
Series K Preferred Shares shall not be redeemable by the Trust prior to January
9, 2017.  On or after January 9, 2017,
the Trust, at its option, may redeem Series K Preferred Shares, in whole or
from time to time in part, at the Redemption Price.


(b)                                 In
the event of a redemption of Series K Preferred Shares, if the Redemption Date
occurs after a Dividend Record Date and on or prior to the related Dividend
Payment Date, the dividend payable on such Dividend Payment Date in respect of
such shares called for redemption shall be payable on such Dividend Payment
Date to the holders of record at the close of business on such Dividend Record
Date and shall not be payable as part of the Redemption Price for such
shares.  If full cumulative dividends on
all outstanding Series K Preferred Shares have not been paid or declared and
set apart for payment, no Series K Preferred Shares may be redeemed unless all
outstanding Series K Preferred Shares are simultaneously redeemed and neither
the Trust nor any Affiliate of the Trust may purchase or acquire Series K
Preferred Shares, otherwise than pursuant to a purchase or exchange offer made
on the same terms to all holders of Series K Preferred Shares.


(c)                                  If
fewer than all the outstanding Series K Preferred Shares are to be redeemed,
the Trust will select those Series K Preferred Shares to be redeemed pro rata
in proportion to the numbers of Series K Preferred Shares held by holders (with
adjustment to avoid redemption of fractional shares) or by lot or in such other
manner as the Board of Trustees may determine. 
If fewer than all Series K Preferred Shares represented by any
certificate (which may include a global certificate) are redeemed, then a new
certificate (including, if appropriate, a new global certificate) representing
the unredeemed Series K Preferred Shares shall be issued without cost to the
holders thereof.


(d)                                 If
the Trust shall redeem Series K Preferred Shares pursuant to this Section 5,
notice of the redemption shall be mailed by the Trust not less than 30 days nor
more than 60 days prior to the Redemption Date to each holder of record of the
Series K Preferred Shares to be redeemed (the “Redemption Notice”).  Such Redemption Notice shall be provided by
first class mail, postage prepaid, at such holder’s address as the same appears
on the share records of the Trust. 
Neither the failure to mail the Redemption Notice, nor any defect
therein or in the mailing thereof to any particular holder, shall affect the
sufficiency of the Redemption Notice or the validity of the proceedings for
redemption with respect to the other holders. 
A Redemption Notice which has been mailed in the manner herein provided
shall be conclusively presumed to have been duly given on the date mailed
whether or not the holder receives the Redemption Notice.  Each Redemption Notice shall state, as
appropriate: (i) the Redemption Date; (ii) the number of Series K Preferred
Shares to be redeemed; (iii) the manner in which Series K Preferred Shares are
to be surrendered, including the requisite form of documentation for such
surrender of Series K Preferred Shares to the Trust; and (iv) the Redemption
Price payable on such Redemption Date, including, without limitation, a
statement as to whether or not accrued and unpaid dividends will be (x) payable
as part of the Redemption Price, or (y) payable on the



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next Dividend Payment
Date to the record holder at the close of business on the relevant Record Date
as described in the next succeeding sentence. 
A Redemption Notice having been mailed as aforesaid, from and after the
Redemption Date (unless the Trust shall fail to set apart for payment the
amount of cash necessary to effect such redemption), (i) dividends on the
Series K Preferred Shares so called for redemption shall cease to accrue on
said shares, (ii) said shares shall no longer be deemed to be outstanding, and
(iii) all rights of the holders thereof as holders of Series K Preferred Shares
shall cease, except (a) the right to receive the Redemption Price, without
interest thereon, and (b) if the Redemption Date for any Series K Preferred
Shares occurs after any Dividend Record Date and on or prior to the related
Dividend Payment Date, the full dividend payable on such Dividend Payment Date
in respect of such Series K Preferred Shares called for redemption shall be
payable on such Dividend Payment Date to the holders of record of such shares
at the close of business on the corresponding Dividend Record Date
notwithstanding the prior redemption of such shares.  The Trust’s obligation to make available the
cash necessary to effect such redemption in accordance with the preceding
sentence shall be deemed fulfilled if, on or before the applicable Redemption
Date, the Trust shall irrevocably deposit in trust with a bank or trust company
(which may not be an Affiliate of the Trust) that has, or is an Affiliate of a
bank or trust company that has, a capital and surplus of at least $50,000,000,
such amount of cash as is necessary for such redemption plus, if such
Redemption Date occurs after any Dividend Record Date and on or prior to the
related Dividend Payment Date, such amount of cash as is necessary to pay the
dividend payable on such Dividend Payment Date in respect of such Series K
Preferred Shares called for redemption, with irrevocable instructions that such
cash be applied to the redemption of the Series K Preferred Shares so called
for redemption and, if applicable, the payment of such dividend.  No interest shall accrue for the benefit of
the holders of Series K Preferred Shares to be redeemed on any cash so set
aside by the Trust.  Subject to
applicable escheat laws, any such cash unclaimed at the end of two years from
the Redemption Date shall revert to the general funds of the Trust, after which
reversion the holders of Series K Preferred Shares so called for redemption
shall look only to the general funds of the Trust for the payment of such
cash.  As promptly as practicable after
the surrender in accordance with the Redemption Notice of any such Series K
Preferred Shares to be so redeemed (in the case of certificated shares,
properly endorsed or assigned for Transfer, if the Trust shall so require and
the Redemption Notice shall so state), such surrendered Series K Preferred
Shares shall be exchanged for cash (without interest thereon) for which such
Series K Preferred Shares have been redeemed in accordance with such Redemption
Notice.


6.                                    CONVERSION AT OPTION OF THE HOLDER.


Holders of Series K Preferred Shares shall have the
right to convert all or a portion of such shares into Common Shares, as
follows:


(a)                                  Subject to and upon compliance with the
provisions of this Section 6, a holder of Series K Preferred Shares shall have
the right, at such holder’s option, at any time, to convert such shares, in
whole or in part, into the number of fully paid and nonassessable shares of
authorized but previously unissued Common Shares obtained by dividing (1) an
amount equal to the aggregate Liquidation Preference of the Series K Preferred
Shares to be converted by (2) an amount equal to (A) the Calculation Price
multiplied by (B) 1.25.  Such conversion
shall be caused by the surrender of such shares to be converted, such surrender
to be made in the manner



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provided in Section 6(b) of this Article.


(b)                                 In order to exercise the conversion right, the
holder of each Series K Preferred Share to be converted shall surrender the
certificate representing such shares, duly endorsed or assigned to the Trust or
in blank, at the office of the Transfer Agent, accompanied by written notice to
the Trust that the holder thereof elects to convert such Series K Preferred
Shares.  Unless the shares issuable on
conversion are to be issued in the same name as the name in which such Series K
Preferred Shares are registered, each share surrendered for conversion shall be
accompanied by instruments of transfer, in form reasonably satisfactory to the
Trust, duly executed by the holder or such holder’s duly authorized attorney,
and an amount sufficient to pay any transfer or similar tax (or evidence
reasonably satisfactory to the Trust demonstrating that such taxes have been
paid) as required by Section 6(j) of this Article.  As promptly as practicable after the
surrender of certificates for Series K Preferred Shares as aforesaid, the Trust
shall issue and shall deliver at such office to such holder, or send on such
holder’s written order, a certificate or certificates for the number of full
Common Shares issuable upon the conversion of such Series K Preferred Shares in
accordance with provisions of this Section 6, and any fractional interest in
respect of a Common Share arising upon such conversion shall be settled as
provided in Section 6(c) of this Article. 
If all Series K Preferred Shares evidenced by any certificate are not
converted, the Trust shall issue and deliver at such office to such holder a
certificate for the remaining Series K Preferred Shares not converted.  Each conversion shall be deemed to have been
effected immediately prior to the close of business on the date on which the
certificates for Series K Preferred Shares shall have been surrendered and such
notice received by the Trust as aforesaid, and the Person or Persons in whose
name or names any certificate or certificates for Common Shares shall be issuable
upon such conversion shall be deemed to have become the holder or holders of
record of the shares represented thereby at such time on such date unless the
share transfer books of the Trust shall be closed on that date, in which event
such Person or Persons shall be deemed to have become such holder or holders of
record at the close of business on the next succeeding day on which such
transfer books are open, provided that such closure of the share transfer books
shall not delay the date on which such Person shall become a holder of such
shares by more than two Business Days.


(c)                                  No fractional Common Share or scrip representing
fractions of a Common Share shall be issued upon conversion of the Series K
Preferred Shares.  Instead of any
fractional interest in a Common Share that would otherwise be deliverable upon
the conversion of Series K Preferred Shares, the Trust shall pay to the holder
of such share an amount in cash based upon the Current Market Price of the
Common Shares on the Trading Day immediately preceding the date of
conversion.  If more than one share shall
be surrendered for conversion at one time by the same holder, the number of
full Common Shares issuable upon conversion thereof shall be computed on the
basis of the aggregate number of Series K Preferred Shares so surrendered.


(d)                                 If the Trust shall be a party to any transaction
(including without limitation a merger, consolidation, statutory share exchange
or reclassification of the Common Shares (each of the foregoing being referred
to herein as a “Transaction”)), in each case as a result of which Common Shares
shall be converted into the right to receive shares, securities or other
property (including cash or any combination thereof), each Series K Preferred
Share which is not converted into the right to receive shares, securities or
other property in connection with such



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Transaction shall thereupon be convertible into the kind and amount of
shares, securities and other property (including cash or any combination
thereof) receivable upon such consummation by a holder of that number of Common
Shares into which one Series K Preferred Share was convertible immediately
prior to such Transaction.  The Trust
shall not be a party to any Transaction unless the terms of such Transaction
are consistent with the provisions of this Section 6(d), and it shall not
consent or agree to the occurrence of any Transaction until the Trust has
entered into an agreement with the successor or purchasing entity, as the case
may be, for the benefit of the holders of the Series K Preferred Shares that
will contain provisions enabling the holders of the Series K Preferred Shares
that remain outstanding after such Transaction to convert into the
consideration received by holders of Common Shares in accordance with the conversion
rate established pursuant to Section 6(a) of this Article, as it may be
adjusted pursuant to this Section 6.  The
provisions of this Section 6(d) shall similarly apply to successive
Transactions.


(e)                                  If there shall be any reclassification of the Common
Shares or any consolidation or merger to which the Trust is a party and for
which approval of any shareholders of the Trust is required, or a statutory
share exchange, or the voluntary or involuntary liquidation, dissolution and
winding up of the Trust, then the Trust shall cause to be mailed to each holder
of Series K Preferred Shares at such holder’s address as shown on the records
of the Trust, as promptly as possible, but at least 15 days prior to the
applicable date hereinafter specified, a notice stating the date on which such
reclassification, consolidation, merger, statutory share exchange or
liquidation, dissolution and winding up is expected to become effective, and
the date as of which it is expected that holders of Common Shares of record shall
be entitled to exchange their Common Shares for securities or other property,
if any, deliverable upon such event. 
Failure to give or receive such notice or any defect therein shall not
affect the legality or validity of the proceedings described in this Section 6.


(f)                                    (i)   In the event the Trust
should at any time or from time to time after the date of issuance of the
Series K Preferred Shares fix a record date for the effectuation of a split or
subdivision of the outstanding Common Shares or the determination of holders of
Common Shares entitled to receive a dividend or other distribution payable in
additional Common Shares without payment of any consideration by such holder
for the additional Common Shares, then, as of such record date (or the date of
such dividend distribution, split or subdivision if no record date is fixed),
the Calculation Price shall be appropriately decreased so that the number of
Common Shares issuable on conversion of each Series K Preferred Share shall be
increased in proportion to such increase of outstanding Common Shares.  If the number of Common Shares outstanding at
any time after the date of issuance of the Series K Preferred Shares is
decreased by a combination of the then outstanding Common Shares, then,
following the record date of such combination (or the date of such combination
if no record date is fixed), the Calculation Price for the Series K Preferred
Shares shall be appropriately increased so that the number of shares of Common
Stock issuable on conversion of each Series K Preferred Share shall be
decreased in proportion to such decrease in outstanding Common Shares.  Whenever the Calculation Price is adjusted as
herein provided, the Trust shall promptly file with the Transfer Agent an
officer’s certificate setting forth the Calculation Price after such adjustment
and setting forth a brief statement of the facts requiring such adjustment
which certificate shall be conclusive evidence of the correctness of such
adjustment absent manifest error. 
Promptly after delivery of



 10
 








such certificate, the Trust shall prepare a notice of such adjustment
setting forth the adjusted Calculation Price and the effective date such
adjustment becomes effective and shall mail such notice of such adjustment to
each holder of Series K Preferred Shares at such holder’s last address as shown
on the share records of the Trust.


(ii)   In the event the Trust at any
time, or from time to time, shall make or issue, or fix a record date for the
determination of holders of Common Shares entitled to receive, a dividend or
other distribution payable in securities of the Trust other than Common Shares,
then and in each such event, provision shall be made so that the holders of
Series K Preferred Shares shall receive upon conversion thereof, in addition to
the number of Common Shares receivable thereupon, the amount of securities of
the Trust which they would have received had their Series K Preferred Shares
been converted into Common Shares on the date of such event and had thereafter,
during the period from the date of such event to and including the date of
conversion, retained such securities receivable by them as aforesaid during
such period, giving application to all adjustments called for during such
period under this Section 6(f) with respect to the rights of the holders of
Series K Preferred Shares.


(g)                                 In any case in which Section 6(f) of this Article
provides that an adjustment shall become effective on the day next following
the record date for an event, the Trust may defer until the occurrence of such
event (A) issuing to the holder of any Series K Preferred Share converted after
such record date and before the occurrence of such event the additional Common
Shares issuable upon such conversion by reason of the adjustment required by
such event over and above the Common Shares issuable upon such conversion
before giving effect to such adjustment and (B) paying to such holder any
amount of cash in lieu of any fraction pursuant to Section 6(c) of this
Article; provided, however, that the holder of such Series K
Preferred Shares shall be entitled to such additional Common Shares and cash,
as applicable, upon such event.


(h)                                 There shall be no adjustment of the Calculation
Price in case of the issuance of any capital shares of the Trust, including issuance
in connection with a reorganization, acquisition or other similar transaction
except as specifically set forth in this Section 6.  If any action or transaction would require
adjustment of the Calculation Price pursuant to more than one paragraph of this
Section 6, only one adjustment shall be made and such adjustment shall be the
amount of adjustment that has the highest absolute value to the holder of
Series K Preferred Shares.


(i)                                     The Trust shall at all times reserve and keep
available, free from preemptive rights, out of the aggregate of its authorized
but unissued Common Shares solely for the purpose of effecting conversion of
the Series K Preferred Shares, the full number of Common Shares deliverable
upon the conversion of all outstanding Series K Preferred Shares not
theretofore converted into Common Shares. 
For purposes of this Section 6(i), the number of Common Shares that
shall be deliverable upon the conversion of all outstanding Series K Preferred
Shares shall be computed as if at the time of computation all such outstanding
shares were held by a single holder.  The
Trust covenants that any Common Shares issued upon conversion of the Series K
Preferred Shares shall be validly issued, fully paid and non-assessable.  The Trust shall list the Common Shares
required to be delivered upon conversion of the Series K Preferred Shares,
prior to such delivery, upon each national securities exchange, if any, upon
which the



 11
 








outstanding Common Shares are listed at the time of such delivery.


(j)                                     The Trust will pay any and all documentary stamp
or similar issue or transfer taxes payable in respect of the issue or delivery
of Common Shares or other securities or property on conversion of Series K
Preferred Shares pursuant hereto; provided, however, that the Trust
shall not be required to pay any tax that may be payable in respect of any
transfer involved in the issue or delivery of Common Shares or other securities
or property in a name other than that of the holder of the Series K Preferred
Shares to be converted, and no such issue or delivery shall be made unless and
until the Person requesting such issue or delivery has paid to the Trust the
amount of any such tax or established, to the reasonable satisfaction of the
Trust, that such tax has been paid.


7.                                      STATUS
OF REACQUIRED SHARES.


All Series K
Preferred Shares that have been issued and are reacquired in any manner by the
Trust (including, without limitation, Series K Preferred Shares which are
redeemed) shall be returned to the status of authorized but unissued Preferred
Shares, without designation as to series. 
The Trust may also retire any unissued Series K Preferred Shares, and
such shares shall then be restored to the status of authorized but unissued
Preferred Shares without designation as to series.  In no event shall any
retired Series K Preferred Shares, or any other retired Preferred
Shares, be reissued as Series K Preferred Shares.


8.                                      RANKING.


The Series K Preferred Shares will, with respect to
dividend rights and rights upon the liquidation, dissolution or winding-up of
the Trust, rank:


(a)                                  prior
or senior to the Common Shares and any other class or series of the Trust’s
Equity Shares authorized or designated in the future if the holders of Series K
Preferred Shares shall be entitled to the receipt of dividends or of amounts
distributable upon liquidation, dissolution or winding-up in preference or
priority to the holders of shares of such class or series (“Junior Shares”);


(b)                                 on
a parity with the Series G Preferred Shares, Series H Preferred Shares, Series
J Preferred Shares and any other class or series of the Trust’s Equity Shares
authorized or designated in the future if, by the terms of such class or
series, the holders of such class or series of securities and the Series K
Preferred Shares shall be entitled to the receipt of dividends and of amounts
distributable upon liquidation, dissolution or winding-up in proportion to
their respective amounts of accrued and unpaid dividends per share or
liquidation preferences, without preference or priority of one over the other (“Parity
Shares”); and


(c)                                  junior
to any class or series of Equity Shares authorized or designated in the future
if, by the terms of such class or series, the holders of such class or series
shall be entitled to the receipt of dividends and amounts distributable upon
liquidation, dissolution or winding-up in preference or priority to the holders
of the Series K Preferred Shares (“Senior Shares”).



 12
 








9.                                      VOTING.


(a)                                  If
and whenever six (6) quarterly dividends (whether or not consecutive) payable
on the Series K Preferred Shares or any series or class of Parity Shares shall
be in arrears (which shall, with respect to any such quarterly dividend, mean
that any such dividend has not been paid in full), whether or not declared, the
number of Trustees then constituting the Board of Trustees shall be increased
by two (if not already increased by reason of similar types of provisions with
respect to Parity Shares of any other class or series which is entitled to
similar voting rights (the “Voting Parity Shares”); without limiting the
foregoing, the Series G Preferred Shares, Series H Preferred Shares and Series
J Preferred Shares shall be deemed to be entitled to voting rights similar to
the Series K Preferred Shares) and the holders of Series K Preferred Shares,
together with the holders of all other Voting Parity Shares then entitled to
exercise similar voting rights, voting as a single class regardless of series
or class, shall be entitled to elect the two additional Trustees to serve on the
Board of Trustees at any annual meeting of shareholders or at a special meeting
of the holders of the Series K Preferred Shares and the Voting Parity Shares
called as hereinafter provided.  At any
time when such right to elect Trustees separately shall have been so vested in
the holders of Series K Preferred Shares and the Voting Parity Shares, if
applicable, the Secretary of the Trust may, and upon the written request of the
holders of record of not less than 20% of the total number of Series K
Preferred Shares and Voting Parity Shares (addressed to the Secretary at the
principal office of the Trust) shall, call a special meeting of the holders of
the Series K Preferred Shares and of the Voting Parity Shares for the election
of the two Trustees to be elected by them as herein provided, such call to be
made by notice similar to that provided in the Bylaws of the Trust for a
special meeting of the shareholders or as required by law.  Such special meeting shall be held, in the
case of such written request, within 90 days after the delivery of such
request, provided that the Trust shall not be required to call such a special
meeting if such request is received less than 120 days before the date fixed
for the next ensuing annual meeting of shareholders and the holders of the
Series K Preferred Shares and Voting Parity Share are offered the opportunity
to elect such Trustees at such annual meeting. 
The Trustees elected at any such special meeting shall hold office until
the next annual meeting of the shareholders or special meeting held in lieu
thereof if such office shall not have previously terminated as provided
herein.  If any vacancy shall occur among
the Trustees elected by the holders of the Series K Preferred Shares and the
Voting Parity Shares by reason of death, resignation or disability, a successor
shall be elected by the Board of Trustees, upon the nomination of the
then-remaining Trustee elected by the holders of the Series K Preferred Shares
and the Voting Parity Shares or the successor of such remaining Trustee, to
serve until the next annual meeting of the shareholders or special meeting held
in place thereof if such office shall not have previously terminated as
provided above.  Whenever all arrears in
dividends on the Series K Preferred Shares and the Voting Parity Shares then
outstanding shall have been paid and dividends thereon for the current Dividend
Period shall have been declared and paid, or declared and set apart for
payment, then the right of the holders of the Series K Preferred Shares and the
Voting Parity Shares to elect such additional two Trustees shall cease (but
subject always to the same provision for the vesting of such voting rights in
the case of any similar future arrearages), and the terms of office of all
persons elected as Trustees by the holders of the Series K Preferred Shares and
the Voting Parity Shares shall forthwith terminate and the number of Trustees
constituting the Board of Trustees shall be reduced accordingly.



 13
 








(b)                                 So
long as any Series K Preferred Shares are outstanding, in addition to any other
vote or consent of shareholders required by law or by the Declaration of Trust
of the Trust, the affirmative vote or consent of at least sixty-six and
two-thirds percent (66-2/3%) of the votes entitled to be cast by the holders of
the outstanding Series K Preferred Shares voting as a single class with the
holders of all other classes or series of Voting Parity Shares entitled to vote
on such matters, given in person or by proxy, either in writing without a
meeting or by vote at any meeting called for the purpose, shall be necessary
for effecting or validating:


(i)                                     Any
amendment, alteration or repeal of any of the provisions of, or the addition of
any provision to, these Articles Supplementary, the Declaration of Trust or the
By-Laws of the Trust that materially adversely affects the voting powers,
rights or preferences of the holders of the Series K Preferred Shares; provided,
however, that the amendment of or supplement to the provisions of the
Declaration of Trust to authorize, create, increase or decrease the authorized
amount of, or to issue Junior Shares, Series K Preferred Shares or any class of
Parity Shares shall not be deemed to materially adversely affect the voting
powers, rights or preferences of the holders of Series K Preferred Shares; or


(ii)                                  The
authorization, creation of, increase in the authorized amount of, or issuance
of shares of any class or series of Senior Shares or any security convertible
or exchangeable into shares of any class or series of Senior Shares (whether or
not such class or series of Senior Shares is currently authorized);


provided,
however, that no such vote of the holders of Series K Preferred Shares
shall be required if, at or prior to the time when such amendment, alteration
or repeal is to take effect, or when the issuance of any such Senior Shares or
convertible or exchangeable security is to be made, as the case may be,
provision is made for the redemption of all outstanding Series K Preferred
Shares to the extent such redemption is authorized by Section 5 of this
Article.


For purposes of
the foregoing provisions and all other voting rights under these Articles
Supplementary, each Series K Preferred Share shall have one (1) vote per share,
except that when any other class or series of preferred shares of the Trust
shall have the right to vote with the Series K Preferred Shares as a single
class on any matter, then the Series K Preferred Shares and such other class or
series shall have with respect to such matters one half of one vote per $50.00
of stated liquidation preference.  Except
as otherwise required by applicable law or as set forth herein or in the
Declaration of Trust, the Series K Preferred Shares shall not have any
relative, participating, optional or other special voting rights and powers
other than as set forth herein, and the consent of the holders thereof shall
not be required for the taking of any action by the Trust.


10.                               RECORD
HOLDERS.


The Trust and the
Transfer Agent may deem and treat the record holder of any Series K Preferred
Share as the true and lawful owner thereof for all purposes, and neither the
Trust nor the Transfer Agent shall be affected by any notice to the contrary.



 14
 








11.                               RESTRICTIONS
ON OWNERSHIP AND TRANSFER; REMEDIES.


Article VII of the
Declaration of Trust sets forth certain ownership and transfer restrictions
relating to the Equity Shares, including the Series K Preferred Shares.  Article VII of the Declaration of Trust is
hereby incorporated by reference herein.


FOURTH:
These Articles Supplementary have been duly adopted by all necessary action on
the part of the Trust.



 15















IN WITNESS WHEREOF, the Trust has caused these presents to be signed in its name and on its
behalf by its President and Chief Executive Officer and witnessed by its
Secretary, Vice President and General Counsel on January 9, 2007.


	
  WITNESS:

  	
   

  	
  CORPORATE OFFICE PROPERTIES TRUST

  
	
   

  	
   

  	
   

  
	
  /s/ Karen M. Singer

  	
   

  	
   

  	
  /s/ Randall M. Griffin

  	
   

  
	
  Name:  Karen M. Singer

  	
   

  	
  Name: Randall M. Griffin

  
	
  Title:    Secretary, Senior Vice
  President

  & General Counsel

  	
   

  	
  Title:   President
  and Chief Executive Officer

  
					



 


THE UNDERSIGNED,
Secretary, Vice President and General Counsel of CORPORATE OFFICE PROPERTIES
TRUST, hereby acknowledges in the name and on behalf of said Trust the
foregoing Articles Supplementary to be the official act of said Trust and
hereby certifies that the matters and facts set forth herein with respect to
the authorization and approval thereof are true in all material respects under
the penalties of perjury.


 


	
  /s/ Karen M. Singer

  	
   

  
	
  Name:  Karen M. Singer

  
	
  Title:    Secretary, Senior Vice
  President and General

  Counsel