<PAGE>
                                                                    Exhibit 10.4


                         PLEDGE AND SECURITY AGREEMENT

          This PLEDGE AND SECURITY AGREEMENT (as amended, supplemented or
modified from time to time, this "Pledge Agreement") is dated as of May 15,
2000, and is by ALCANTARA LLC, a Delaware limited liability company without
managers (the "Pledgor") in favor of BANK OF AMERICA, N.A., a national banking
association (the "Pledgee").

          MicroStrategy Incorporated, a Delaware corporation, (the "Borrower")
and the Bank have entered into a certain Credit Agreement dated March 26, 1999
(as modified by a certain First Modification Agreement dated as of May 15, 2000,
and as from time to time otherwise amended, supplemented and replaced, the
"Credit Agreement"). Terms used herein and defined in the Credit Agreement and
not otherwise defined herein, shall have their meanings herein as therein
defined.  The Pledgor has delivered to the Pledgee its Guaranty of Payment dated
May 15, 2000 (as from time to time amended and replaced, the "LLC Guaranty"),
and Michael J. Saylor (the "Guarantor"), the sole member and sole officer of the
Pledgor, has delivered to the Pledgee his Guaranty of Payment dated May 15, 2000
(as from time to time amended and replaced, the "Personal Guaranty"), to
guaranty in full the payment of all "Obligations" (as defined in the LLC
Guaranty and the Personal Guaranty) (hereinafter, "Loan Obligations").  To
provide collateral security for all of the obligations of the Pledgor under the
LLC Guaranty (the "Guaranty Obligations") and the Loan Obligations, the Pledgor
has requested that the Pledgee accept this Pledge Agreement.  The Pledgee has
agreed to do so, but only upon the terms and conditions set forth herein.
Accordingly, the parties hereto agree as follows:


                                   ARTICLE I
                                  DEFINITIONS

          Section 1.1.  Specifically Defined Terms.  As used in this Pledge
                        --------------------------
Agreement, the following terms shall have the following meanings:

          (a) "Account" means securities account number 859973 maintained by the
Pledgor with the Intermediary, all subacccounts and additional accounts in
connection therewith which are now existing or hereafter arising, and all
replacement accounts for any of the foregoing.

          (b) "Book-entry Treasury Security" has the meaning given to the term
"Book-entry Security" in 31 CFR 357.2(a) or any successor provision.

          (c) "Control of the Borrower" means (i) direct ownership, control, and
power to vote 54% or more of all classes of voting securities of the Borrower
(considered as one class); (ii) direct control over the election or appointment
of a majority of the directors (or individuals exercising similar functions) of
the Borrower; and (iii) the direct power to exercise a controlling influence
over the management and policies of the Borrower.

          (d) "Control of the Pledgor" means (i) direct ownership, control, and
power to vote 100% of the ownership interests in the Pledgor; (ii) direct
control over the election or appointment of all members and officers (or
individuals exercising similar functions) of the Pledgor; and (iii) and the
direct power to exercise a controlling influence over the management and
policies of the Pledgor.
<PAGE>

          (e) "Debt" has the meaning given that term in the Credit Agreement.

          (f) "Intermediary" means Bank of America, N.A., a national banking
association, and its successors, in its capacity as such with regard to the
Account and the other Pledged Collateral.

          (g) Each term specifically defined in any other section of this Pledge
Agreement shall have the meaning given to said term therein.

          Section 1.2.  UCC Terms.  Unless otherwise specifically defined
                        ---------
herein, or unless the context otherwise requires, all terms used herein which
are defined in the Virginia Uniform Commercial Code shall have the meanings
therein stated.  As used herein, "UCC" means at any time the Virginia Uniform
Commercial Code; provided that, if, by reason of mandatory provisions of law,
                 --------
the validity or perfection of any security interest granted herein is governed
by the Uniform Commercial Code as in effect in a jurisdiction other than the
Commonwealth of Virginia, then, as to the validity or perfection of such
security interest, "UCC" shall mean the Uniform Commercial Code in effect in
such other jurisdiction.  In the event "UCC" is construed to mean the Uniform
Commercial Code in effect in a jurisdiction other than Virginia, then specific
Uniform Commercial Code references herein shall be construed to mean the
corresponding Uniform Commercial Code provision in such other jurisdiction.


                                  ARTICLE II
                            THE SECURITY INTERESTS

          Section 2.1.    The Security Interests.  The Pledgor hereby pledges to
                          ----------------------
the Pledgee, and grants to the Pledgee a security interest in, the following
(the "Pledged Collateral"):

          (i)    the Account;

          (ii)   all cash, investment property, financial assets, security
entitlements, securities, commodity contracts and instruments which are now or
may hereafter be held, contained or deposited in, arising under, or subject to,
the Account, including, without limitation, those listed on Schedule 1 hereto,
and all additions thereto and substitutions and replacements therefor (the
"Listed Assets"); and all dividends, distributions, cash, instruments and other
property and proceeds from time to time received, receivable or otherwise made
upon or distributed in respect of or in exchange for any or all of the Listed
Assets;

          (iii)  all additional investment property and financial assets from
time to time acquired by the Pledgor in any manner and held or subject to the
Account and all dividends, distributions, cash, instruments and other property
from time to time received, receivable or otherwise made upon or distributed in
respect of or in exchange for any or all of such securities;


                                      -2-
<PAGE>

          (iv)   all rights of the Pledgor against the Intermediary or any other
third party arising out of the Account, or any instrument or agreement in
connection therewith in which the Pledgor has rights;

          (v)    all general intangibles now existing or hereafter arising
with respect to any of the foregoing;

          (vi)   all instruments, security certificates and other
certificates representing any of the foregoing; and

          (vii)  to the extent not otherwise included in the foregoing, all
cash and non-cash proceeds thereof.

          Section 2.2.  Security for Obligations.  This Pledge Agreement secures
                        ------------------------
the payment of all Guaranty Obligations and Loan Obligations. The security
interests granted by this Pledge Agreement are granted as security only and
shall not subject the Pledgee to, or transfer or in any way affect or modify,
any obligation or liability of the Pledgor with respect to the Account, any of
the Pledged Collateral, or any transaction in connection therewith.

          Section 2.3.  Control of Pledged Collateral.  All Pledged Collateral
                        -----------------------------
shall be pledged or transferred to the Pledgee so as to create a perfected first
priority security interest therein in favor of the Pledgee through control of
the Pledged Collateral by the Pledgee in accordance with applicable provisions
of the UCC.  Without limiting in any way the foregoing:

          (a)    All security certificates, other certificates, and instruments
representing or evidencing the Pledged Collateral shall be delivered to and held
by the Pledgee, or by the Intermediary on behalf of the Pledgee, pursuant hereto
and to Section 8.8A-301(a) or 8.9-304, as applicable, of the UCC, and shall be
in suitable form for transfer by delivery, or shall be accompanied by duly
executed instruments of transfer or assignment in blank, or specially indorsed
to the Pledgee, with signatures appropriately guaranteed, and accompanied in
each case by any required documentary or transfer tax stamps, and any other
documents necessary or, in the sole discretion of the Pledgee, desirable, to
cause the Pledgee to have control of (within the meaning of Sections 8.9-115(e)
and 8.8A-106 of the UCC) and a security interest in the Pledged Collateral, all
in form and substance satisfactory to the Pledgee.  The Pledgee shall have the
right, at any time in its discretion and without notice to the Pledgor, to cause
any or all of such Pledged Collateral to be transferred of record into the name
of the Pledgee or its nominee.  All such certificates or instruments held by the
Intermediary shall be segregated from all other securities or other assets of
the Pledgor or the Pledgee or any other person held by the Intermediary in any
capacity other than as Intermediary hereunder.

          (b)    With respect to all Pledged Collateral consisting of
uncertificated securities, the Pledgor shall cause, as appropriate, (i) each
issuer of said Pledged Collateral to agree in writing that it will comply with
instructions originated by the Pledgee without further consent by the Pledgor or
other registered owner; or (ii) said Pledged Collateral to be delivered to and
held by the Pledgee

                                      -3-
<PAGE>

pursuant hereto and to Section 8.8A-301(b) of the UCC. The Pledgee shall have
the right, at any time in its discretion and without notice to the Pledgor, to
cause any or all of such Pledged Collateral to be transferred of record into the
name of the Pledgee or its nominee.

          (c)    With respect to all Pledged Collateral consisting of security
entitlements, the Pledgor shall (i) issue its entitlement order to the
Intermediary instructing that the Pledgee be forthwith identified in the
Intermediary's records as the entitlement holder of said Pledged Collateral, or
(ii) cause the Intermediary to agree in writing that it will comply with
entitlement orders originated by the Pledgee without further consent by the
Pledgor or other entitlement holder.

          (d)    With respect to all Pledged Collateral consisting of commodity
contracts, the Pledgor shall cause the Intermediary to agree, in a writing
executed by the Intermediary, the Pledgor and the Pledgee, that the Intermediary
will apply any value distributed on account of said commodity contracts as
directed by the Pledgee without further consent by the Pledgor or other
commodity customer.

          (e)    With respect to all Pledged Collateral consisting of Book-entry
Treasury Securities, the Pledgor shall (i) (A) issue its entitlement order to
the Intermediary instructing that the Pledgee be forthwith identified in the
Intermediary's records as the entitlement holder of said Pledged Collateral, or
(B) cause the Intermediary to agree in writing that it will comply with
entitlement orders originated by the Pledgee without further consent by the
Pledgor or other entitlement holder, and (ii) use its best efforts to have, or
cause the Intermediary to use its best efforts to have, the appropriate Federal
Reserve Bank (or Banks) mark its books and records to record the security
interest of the Pledgee in such Pledged Collateral.

          (f)    The Pledgor shall otherwise cause the Pledgee to obtain control
over the Account in accordance with Section 8.9-115(e) of the UCC.

          (g)    The Pledgor shall cause the Intermediary, and any secured party
other than the Pledgee having control of any of the Pledged Collateral, to
subordinate in writing its security interest in the Pledged Collateral (whether
arising by contract or under the UCC or other applicable law) to that of the
Pledgee granted herein.

          (h)    The Pledgor shall execute and deliver to the Pledgee UCC
financing statements and continuation statements to be filed by the Pledgor in
all applicable jurisdictions as required to perfect the security interests
granted to the Pledgee hereunder, to the extent that applicable law permits
perfection of a security interest by filing under the UCC.

          Section 2.4.   Termination of Security Interests; Release of Pledged
                         -----------------------------------------------------
Collateral.  Upon the full, final and irrevocable payment and performance of all
----------
the Guaranty Obligations and Loan Obligations, the security interests in the
Pledged Collateral shall terminate and all rights to the Pledged Collateral
shall revert to the Pledgor.  In addition, at any time and from time to time
prior to such termination of the security interests, the Pledgee may release any
of the Pledged Collateral.  Upon any

                                      -4-
<PAGE>

such termination of the security interests or any release of the Pledged
Collateral, the Pledgee will, at the Pledgor's expense, execute and deliver to
the Pledgor such documents as the Pledgor shall reasonably request to evidence
the termination of the security interests or the release of the Pledged
Collateral. Any such documents shall be without recourse to or warranty by the
Pledgee.

          Section 2.5.  Security Interests Absolute.  Subject to the provisions
                        ---------------------------
of Section 2.4, all rights of the Pledgee and security interests hereunder, and
all obligations of the Pledgor hereunder, shall be absolute and unconditional
and, without limiting the generality of the foregoing, shall not be released,
discharged or otherwise affected by:

          (i)    any extension, renewal, settlement, compromise, waiver or
release in respect of any Loan Obligation or Guaranty Obligation, or any other
document evidencing or securing such Loan Obligation or Guaranty Obligation, by
operation of law or otherwise;

          (ii)   any modification or amendment or supplement to the Credit
Agreement, the LLC Guaranty, the Personal Guaranty, or any instrument or
document evidencing or securing any Loan Obligation or Guaranty Obligation;

          (iii)  any release, non-perfection or invalidity of any direct or
indirect security for any Loan Obligation or Guaranty Obligation;

          (iv)   the death or incompetence of the Guarantor, or any change in
the existence, structure or ownership of the Borrower, or any insolvency,
bankruptcy, reorganization or other similar proceeding affecting the Borrower or
the Guarantor, or their respective assets or any resulting disallowance, release
or discharge of all or any portion of the Loan Obligations or the Guaranty
Obligations;

          (v)    the existence of any claim, set-off or other right which the
Pledgor may have at any time against the Borrower, the Pledgee, or the
Guarantor, or any other corporation or person, whether in connection herewith or
any unrelated transactions; provided, that nothing herein shall prevent the
                            --------
assertion of any such claim by separate suit or compulsory counterclaim;

          (vi)   any invalidity or unenforceability relating to or against the
Borrower or the Guarantor for any reason of any Loan Obligation or Guaranty
Obligation, respectively, or any provision of applicable law or regulation
purporting to prohibit the payment by the Borrower of the Loan Obligations or
the Pledgor of the Guaranty Obligations;

          (vii)  any failure by the Pledgee (A) to file or enforce a claim
against the Borrower or the Guarantor or their respective estates (in a
bankruptcy or other proceeding), (B) to give notice of the existence, creation
or incurring by the Borrower of any new or additional indebtedness or obligation
under or with respect to the Loan Obligations or Guaranty Obligations, (C) to
commence any action against the Borrower or the Guarantor, (D) to disclose to
the Pledgor any facts which the Pledgee may now or hereafter know with regard to
the Borrower or the Guarantor, or (E) to proceed


                                      -5-
<PAGE>

with due diligence in the collection, protection or realization upon any
collateral securing the Loan Obligations or the Guaranty Obligations; or

          (viii) any other act or omission to act or delay of any kind by the
Borrower or the Guarantor or the Pledgee or any other corporation or person or
any other circumstance whatsoever which might, but for the provisions of this
clause, constitute a legal or equitable discharge of the Pledgor's obligations
hereunder.


                                  ARTICLE III
                        REPRESENTATIONS AND WARRANTIES

          The Pledgor represents and warrants as follows:

          Section 3.1.   Binding Effect.  This Pledge Agreement constitutes a
                         --------------
valid and binding agreement of the Pledgor, enforceable against the Pledgor in
accordance with its terms, except as the enforceability hereof may be limited by
bankruptcy, insolvency or similar laws affecting creditors' rights generally and
by equitable principles of general applicability (regardless of whether such
enforceability is considered in a proceeding in equity or at law).

          Section 3.2.   Title to Pledged Collateral.  The Pledgor lawfully owns
                         ---------------------------
the Pledged Collateral and has good and marketable title thereto, to the extent
of its interest therein, free and clear of any liens (including, without
limitation, state and federal tax liens and issuer's liens) other than the
security interests granted hereby and Liens in favor of the Intermediary.  The
Account is not a margin account.

          Section 3.3.   Validity, Perfection and Priority of Security
                         ---------------------------------------------
Interests.  Upon (i) delivery of all certificates or instruments representing or
evidencing the Listed Assets registered in the Pledgee's name to the Pledgee,
(ii) the receipt by the Pledgee of an agreement in the form set forth as Exhibit
A hereto, appropriately completed and fully executed, and (iii) the proper
filing of UCC financing statements covering the Pledged Collateral in the
jurisdictions listed on Exhibit B hereto, the Pledgee will have a valid and
perfected security interest in the Pledged Collateral subject to no prior Lien,
other than the security interest of the United States with respect to Book-entry
Treasury Securities as set forth in 31 CFR 357.12(b) or Liens in favor of the
Intermediary.  Except for the filing of financing statements, no registration,
recordation or filing with any governmental authority is required in connection
with the execution or delivery of this Pledge Agreement, or necessary for the
validity or enforceability hereof or for the perfection of the security
interests of the Pledgee granted hereby.  The Pledgor has not performed any acts
which might prevent the Pledgee from enforcing any of the terms and conditions
of this Pledge Agreement or which would limit the Pledgee in any such
enforcement.

          Section 3.4.   Governmental and Other Authorization; Contravention  .
                         ---------------------------------------------------
The execution, delivery and performance by the Pledgor of this Pledge Agreement
and the other instruments and agreements executed and delivered, or to be
executed and delivered, by it are within its

                                      -6-
<PAGE>

organizational power, have been duly authorized by all necessary action of its
members, require no action by or in respect of, or filing with, any governmental
body, agency or official (other than the filing of financing statements) and do
not contravene, or constitute (with or without the giving of notice or lapse of
time or both) a default under, any provision of applicable law or of any
operating agreement or other organizational documents of the Pledgor or of any
agreement, judgment, injunction, order, decree or other instrument binding upon
or affecting the Pledgor or result in the creation or imposition of any lien on
any of its assets.

          Section 3.5.   Book-Entry Treasury Securities.  All Pledged Collateral
                         ------------------------------
consisting of Book-entry Treasury Securities is maintained in "TRADES" and not
in "TREASURY DIRECT" (as those terms are defined in 31 CFR 357.2(a) or any
successor provision).

          Section 3.7.   Existence and Power.   The Pledgor is a limited
                         -------------------
liability company duly organized, validly existing and in good standing under
the laws of the State of Delaware, and has all organizational powers and all
material governmental licenses, authorizations, consents and approvals required
to carry on its business as now conducted.  The Pledgor is duly qualified as a
foreign entity, licensed and in good standing in each jurisdiction in which the
failure to so qualify or be licensed, as the case may be, in the aggregate,
could reasonably be expected to have a material adverse effect on the business,
financial position, results of operations or properties of the Pledgor.

          Section 3.8.  Debt.  The Pledgor has no Debt other than Debt to the
                        ----
Bank.

          Section 3.9.  Control.  The Pledgor has Control of the Borrower and
                        -------
the Guarantor has Control of the Debtor.


                                  ARTICLE IV
                                  COVENANTS

          The Pledgor agrees that so long as any Guaranty Obligation or Loan
Obligation remains unpaid:

          Section 4.1.   Filing; Further Assurances.  The Pledgor will, at its
                         --------------------------
expense and in such manner and form as the Pledgee may reasonably require,
execute, deliver, file and record any financing statement, specific assignment
or other appropriate paper and take any other action that may be reasonably
necessary or desirable, or that the Pledgee may reasonably request, in order to
create, preserve, perfect or validate the security interests granted hereby or
to enable the Pledgee to exercise and enforce its rights hereunder with respect
to any of the Pledged Collateral.  To the extent permitted by applicable law,
the Pledgor hereby authorizes the Pledgee to execute and file, in the name of
the Pledgor or otherwise, UCC financing statements which the Pledgee reasonably
may deem necessary or appropriate to further perfect the security interests.

          Section 4.2.   Liens on Pledged Collateral.  The Pledgor will not sell
                         ---------------------------
or otherwise

                                      -7-
<PAGE>

dispose of, or authorize the sale or disposition of, or grant any option with
respect to, any of the Pledged Collateral or create or suffer to exist any Lien
(other than security interests in favor of the Pledgee, the Lien of the
Intermediary and the security interest of the United States with respect to
Book-entry Treasury Securities as set forth in 31 CFR 357.12(b)) on any Pledged
Collateral. The Account shall not become a margin account. The Pledgor agrees
that it will cause the Intermediary to obtain, and hold in the Account subject
to the security interest granted in the Pledge Agreement, all Listed Assets and
all investment property in addition to or in substitution for the Listed Assets.

          Section 4.3.   Debt.  The Pledgor shall not incur or suffer to exist
                         ----
any Debt other than Debt to the Bank.

          Section 4.4.  Control.  The Pledgor shall at all times maintain
                        -------
Control of the Borrower and the Guarantor shall at all times maintain Control of
the Debtor.


                                   ARTICLE V
                      DISTRIBUTIONS ON COLLATERAL; VOTING

          Section 5.1.    Right to Receive Distributions on Pledged Collateral;
                          -----------------------------------------------------
Voting and Other Rights.
-----------------------

          (a)  So long as no Event of Default has occurred and is continuing,
and subject to the provisions of Section 2.3:

               (i)   The Pledgor shall be entitled to exercise any and all
voting and other rights pertaining to the Pledged Collateral or any part thereof
(including, without limitation, rights of or with respect to conversions,
exchanges, subscriptions, calls, maturities, tenders and options, the right to
make substitutions for uncertificated securities and security entitlements, and
the right to originate instructions and entitlement orders to the issuer or the
Intermediary) for any purpose not inconsistent with the terms of the LLC
Guaranty, the Credit Agreement, or this Pledge Agreement.

               (ii)  The Pledgor shall be entitled to receive and retain any
and all dividends, interest and other payments and distributions made upon or
with respect to the Pledged Collateral, provided, however, that any and all
                                        --------  -------

                     (A)  dividends and interest paid or payable other than in
          cash in respect of, and certificates, instruments and other property
          received, receivable or otherwise distributed in respect of, or in
          exchange for, any Pledged Collateral (including, without limitation,
          any certificate or instrument representing a stock dividend or a
          distribution in connection with any reclassification, increase or
          reduction of capital, or reorganization),


                                      -8-
<PAGE>

                     (B)  dividends and other distributions paid or payable in
          cash in respect of any Pledged Collateral in connection with a partial
          or total liquidation or dissolution or in connection with a reduction
          of capital, capital surplus or paid-in-surplus, and

                     (C)  cash paid, payable or otherwise distributed in respect
          of principal of, in redemption of, or in exchange for, any Pledged
          Collateral,

shall be, and shall be forthwith delivered to the Pledgee or the Intermediary to
hold as, Pledged Collateral and shall, if received by the Pledgor, be received
in trust for the benefit of the Pledgee, be segregated from the other property
or funds of the Pledgor and be forthwith delivered to the Pledgee or the
Intermediary as Pledged Collateral in the same form as so received (with any
necessary indorsement and, if appropriate, undated stock powers duly executed in
blank).

               (iii) The Pledgee shall execute and deliver (or cause to be
executed and delivered) to the Pledgor all such proxies, powers of attorney,
consents, instructions, entitlement orders, ratifications and waivers and other
instruments as the Pledgor may reasonably request for the purpose of enabling
the Pledgor to exercise the voting and other rights which it is entitled to
exercise pursuant to paragraph (i) above and to receive the dividends or
interest payments which it is authorized to receive and retain pursuant to
paragraph (ii) above.

          (b)  Upon the occurrence and during the continuance of an Event of
Default:

               (i)   All rights of the Pledgor to receive the dividends and
interest payments which it would otherwise be authorized to receive and retain
pursuant to Section 5.1(a)(ii) shall cease, and all such rights shall thereupon
become vested in the Pledgee which shall thereupon have the sole right to
receive and hold as Pledged Collateral such dividends and interest payments.

               (ii)  All dividends and interest payments which are received by
the Pledgor contrary to the provisions of paragraph (i) of this Section 5.1(b)
shall be received in trust for the benefit of the Pledgee, shall be segregated
from other funds of the Pledgor and shall be forthwith paid over to the Pledgee
as Pledged Collateral in the same form as so received (with any necessary
indorsement).

          (c)  Upon the occurrence and during the continuance of an Event of
Default and upon notice by the Pledgee to the Pledgor, all rights of the Pledgor
to exercise the voting and other rights which it would otherwise be entitled to
exercise pursuant to Section 5.1(a)(i) shall cease, and all such rights shall
thereupon become vested in the Pledgee who shall thereupon have the sole right
(but in no event any obligation) to exercise such voting and other rights.


                                  ARTICLE VI
                          GENERAL AUTHORITY; REMEDIES

          Section 6.1.   General Authority.  The Pledgor hereby irrevocably
                         -----------------
appoints the

                                      -9-
<PAGE>

Pledgee and any officer or agent thereof, with full power of substitution, as
its true and lawful attorney-in-fact, in the name of the Pledgor or its own
name, for the sole use and benefit of the Pledgee, but at the Pledgor's expense,
at any time and from time to time after the occurrence and during the
continuance of an Event of Default, to take any and all appropriate action and
to execute any and all documents and instruments which may be necessary or
desirable to carry out the terms of this Pledge Agreement and, without limiting
the foregoing, the Pledgor hereby gives the Pledgee the power and right on its
behalf, without notice to or further assent by the Pledgor to do the following:

               (i)   to receive, take, indorse, assign and deliver any and all
checks, notes, drafts, acceptances, documents and other negotiable and non-
negotiable instruments taken or received by the Pledgor as, or in connection
with, the Pledged Collateral;

               (ii)  to demand, sue for, collect, receive and give acquittance
for any and all monies due or to become due upon or in connection with the
Pledged Collateral;

               (iii) to commence, settle, compromise, compound, prosecute,
defend or adjust any claim, suit, action or proceeding with respect to, or in
connection with, the Pledged Collateral;

               (iv)  to sell, transfer, assign or otherwise deal in or with the
Pledged Collateral or any part thereof, as fully and effectually as if the
Pledgee were the absolute owner thereof; and

               (v)   to do, at its option, but at the expense of the Pledgor,
at any time or from time to time, all acts and things which the Pledgee deems
necessary to protect or preserve the Pledged Collateral and to realize upon the
Pledged Collateral.

The Pledgor shall fully cooperate, to the extent requested by the Pledgee, in
the completion of any notice, form, schedule, or other document filed by the
Pledgee on its own behalf or on behalf of the Pledgor pursuant to the Pledgor's
power of attorney, including, without limitation, any required notice or
statement of beneficial ownership or of the acquisition of beneficial ownership
of equity securities constituting part of the Pledged Collateral and any notice
of proposed sale of any such securities pursuant to Rule 144 of the Securities
Exchange Commission.

          Section 6.2.   UCC Rights.  If an Event of Default shall have
                         ----------
occurred, the Pledgee may in addition to all other rights and remedies granted
to it in this Pledge Agreement and in any other agreement securing, evidencing
or relating to the Obligations, exercise (i) all rights and remedies of a
secured party under the UCC (whether or not in effect in the jurisdiction where
such rights are exercised) and (ii) all other rights available to the Pledgee at
law or equity.

          Section 6.3.   Application of Cash; Sale of Pledged Collateral.
                         -----------------------------------------------

          (a)  The Pledgor expressly agrees that if an Event of Default shall
occur and be

                                     -10-
<PAGE>

continuing, the Pledgee, without demand of performance or other demand or notice
of any kind (except the notice specified below of the time and place of any
public or private sale) to or upon the Pledgor or any other person (all of which
demands and notices are hereby waived by the Pledgor), may forthwith (i) apply
the cash, if any, then held by it as Pledged Collateral as specified in Section
6.7 and (ii) if there shall be no such cash or if such cash shall be
insufficient to pay the Obligations in full, to collect, receive, appropriate
and realize upon the Pledged Collateral, and sell, assign, give an option or
options to purchase or otherwise dispose of and deliver the Pledged Collateral
(or contract to do so) or any part thereof in one or more parcels (which need
not be in round lots) at public or private sale, at any office of the Pledgee or
elsewhere in such manner is commercially reasonable and, as the Pledgee may deem
best, for cash or on credit or for future delivery without assumption of any
credit risk. The Pledgee shall have the right upon any such public sale, and, if
the Pledged Collateral is of a type customarily sold in a recognized market or
is of a type which is the subject of widely distributed standard price
quotations, upon any such private sale or sales, to purchase the whole or any
part of the Pledged Collateral so sold, and thereafter to hold the same,
absolutely and free from any right or claim of any kind, provided that any such
sale is conducted in a commercially reasonable manner. To the extent permitted
by applicable law, the Pledgor waives all claims, damages and demands against
the Pledgee arising out of the foreclosure, repossession, retention or sale of
the Pledged Collateral.

          (b)  Unless the Pledged Collateral threatens to decline speedily in
value or is of a type customarily sold on a recognized market, the Pledgee shall
give the Pledgor 10 days' written notice of its intention to make any such
public or private sale or sale at a broker's board or on a securities exchange.
Such notice shall (i) in the case of a public sale, state the time and place
fixed for such sale, (ii) in the case of sale at a broker's board or on a
securities exchange, state the board or exchange at which such sale is to be
made and the day on which the Pledged Collateral, or the portion thereof being
sold, will first be offered for sale and (iii) in the case of a private sale,
state the day after which such sale may be consummated.  The Pledgee shall not
be obligated to make any such sale pursuant to any such notice.  The Pledgee may
adjourn any public or private sale or cause the same to be adjourned from time
to time by announcement at the time and place fixed for the sale, and such sale
may be made at any time or place to which the same may be so adjourned.  In the
case of any sale of all or any part of the Pledged Collateral on credit or for
future delivery, the Pledged Collateral so sold may be retained by the Pledgee
until the selling price is paid by the purchaser thereof, but the Pledgee shall
not incur any liability in case of the failure of such purchaser to take up and
pay for the Pledged Collateral so sold and, in the case of such failure, such
Pledged Collateral may again be sold upon like notice.

          Section 6.4.   Rights of Purchasers.  Upon any sale of the Pledged
                         --------------------
Collateral (whether public or private) pursuant to this Article VI, the Pledgee
shall have the right to deliver, assign and transfer to the purchaser thereof
the Pledged Collateral so sold.  Each purchaser (including the Pledgee) at any
such sale shall hold the Pledged Collateral so sold absolutely, free from any
claim or right whatsoever, including any equity or right of redemption of the
Pledgor who, to the extent permitted by law, hereby specifically waives all
rights of redemption, including, without limitation, any right to redeem the
Pledged Collateral under Section 8.9-506 of the UCC, and any right to a judicial
or other stay or approval which it has or may have under any law now existing or
hereafter adopted.


                                     -11-
<PAGE>

          Section 6.5.   Other Rights of the Pledgee.  So long as an Event of
                         ---------------------------
Default has occurred and is continuing:

          (a)  The Pledgee (i) shall have the right and power (but in no event
the obligation) to institute and maintain such suits and proceedings as it may
deem appropriate to protect and enforce the rights vested in it by this Pledge
Agreement and (ii) may proceed by suit or suits at law or in equity to enforce
such rights and to foreclose upon the Pledged Collateral and to sell all, or
from time to time, any of the Pledged Collateral under the judgment or decree of
a court of competent jurisdiction.

          (b)  The Pledgee shall, to the extent permitted by applicable law,
without notice to the Pledgor or any party claiming through it, without regard
to the solvency or insolvency at such time of any person then liable for the
payment of any of the Guaranty Obligations or the Loan Obligations, without
regard to the then value of the Pledged Collateral and without requiring any
bond from any complainant in such proceedings, be entitled as a matter of right
to the appointment of a receiver or receivers (who may be the Pledgee) of the
Pledged Collateral or any part thereof, and of the profits, revenues and other
income thereof, pending such proceedings, with such powers as the court making
such appointment shall confer, and to the entry of an order directing that the
profits, revenues and other income of the property constituting the whole or any
part of the Pledged Collateral be segregated, sequestered and impounded for the
benefit of the Pledgee, and the Pledgor irrevocably consents to the appointment
of such receiver or receivers and to the entry of such order.

          (c)  In no event shall the Pledgee have any duty (other than the
exercise of reasonable care) to exercise any rights or take any steps (either in
a timely manner or at all) to preserve the rights of the Pledgor in the Pledged
Collateral, nor shall the Pledgee be liable to the Pledgor or any other person
for any loss caused by the Pledgee's failure to meet any obligation imposed by
Section 8.9-207 of the UCC or any successor provision.  Without limiting the
foregoing, the Pledgee shall be deemed to have exercised reasonable care in the
custody and preservation of any of the Pledged Collateral in its actual
possession if the Pledged Collateral is accorded treatment substantially equal
to that which the Pledgee accords its own property, it being understood that the
Pledgee shall not have any duty or responsibility for (i) ascertaining or taking
action with respect to calls, conversions, exchanges, maturities, tenders or
other matters (including, without limitation, the rights described in Section
5.1(a)(i)) relative to any Pledged Collateral, whether or not the Pledgee has or
is deemed to have knowledge of such matters or (ii) taking any necessary steps
to preserve rights against any parties with respect to any Pledged Collateral.
No refusal, failure, omission or delay by the Pledgee in complying with any
request by or on behalf of the Pledgor to do any of the foregoing shall be
deemed to be a failure to exercise reasonable care.

          Section 6.6.   Waiver and Estoppel.
                         -------------------

          (a)  The Pledgor agrees, to the extent it may lawfully do so, that it
will not at any time in any manner whatsoever claim or take the benefit or
advantage of, any appraisal, valuation, stay, extension, moratorium, turnover or
redemption law, or any law permitting it to direct the order in

                                     -12-
<PAGE>

which the Pledged Collateral shall be sold, now or at any time hereafter in
force which may delay, prevent or otherwise affect the performance or
enforcement of this Pledge Agreement, and hereby waives all benefit or advantage
of all such laws. The Pledgor covenants that it will not hinder, delay or impede
the execution of any power granted to the Pledgee in this Pledge Agreement or
any of the other instrument or agreement evidencing or securing a Loan.

          (b)  The Pledgor, to the extent it may lawfully do so, on behalf of
itself and all who claim through or under it, including without limitation any
and all subsequent creditors, vendees, assignees and lienors, waives and
releases all rights to demand or to have any marshalling of the Pledged
Collateral upon any sale, whether made under any power of sale granted herein or
pursuant to judicial proceedings or under any foreclosure or any enforcement of
this Pledge Agreement, and consents and agrees that all of the Pledged
Collateral may at any such sale be offered and sold as an entirety.

          (c)  The Pledgor waives, to the extent permitted by law, presentment,
demand, protest and any notice of any kind (except the notices expressly
required hereunder) in connection with this Pledge Agreement and any action
taken by the Pledgee with respect to the Pledged Collateral.  The Pledgor waives
and agrees not to assert any privileges which it may acquire under Section 8.9-
112 of the UCC.

          Section 6.7.   Application of Moneys.  The proceeds of any sale of, or
                         ----------------------
other realization upon, all or any part of the Pledged Collateral shall be
applied by the Pledgee in the following order of priority (the Pledgor remaining
liable for any deficiency remaining unpaid after such application):

          first, to payment of the expenses of such sale or other realization,
          -----
including reasonable compensation to the Pledgee and its agents and counsel, and
all reasonable expenses, liabilities and advances incurred or made by the
Pledgee, its agents and counsel in connection therewith or in connection with
the care, safekeeping or otherwise of any or all of the Pledged Collateral, and
any other unreimbursed expenses for which the Pledgee is to be reimbursed
pursuant to Section 7.3;

          second, to payment of the Loan Obligations and the Guaranty
          ------
Obligations; and

          finally, any surplus then remaining shall be paid to the Pledgor, or
          -------
its successors or assigns, or to whomsoever may be lawfully entitled to receive
the same or as a court of competent jurisdiction may direct.


                                  ARTICLE VII
                                 MISCELLANEOUS

          Section 7.1.   Notices.  All notices, requests and other
                         -------
communications to any party hereunder shall be in writing and shall be given to
such party at its address set forth on the signature

                                     -13-
<PAGE>

page hereof or to such other address as such party may hereafter specify for the
purpose by notice to the other. Each such notice, request or other communication
shall be effective (i) 5 days after such communication is deposited in the mails
with first class postage prepaid, addressed as aforesaid or (ii) if given by any
other means, when delivered at the address specified in this Section. Rejection
or refusal to accept, or the inability to deliver because of a changed address
of which no notice was given shall not affect the validity of notice given in
accordance with this Section.

          Section 7.2.   Waivers, Non-Exclusive Remedies.  No failure on the
                         -------------------------------
part of the Pledgee to exercise, and no delay in exercising, no course of
dealing with respect to, any right under this Pledge Agreement shall operate as
a waiver thereof; nor shall any single or partial exercise by the Pledgee of any
right under this Pledge Agreement preclude any other or further exercise thereof
or the exercise of any other right.  The rights of the Pledgee under this Pledge
Agreement are cumulative and are not exclusive of any other remedies provided by
law.

          Section 7.3.   Expenses; Documentary Taxes.  The Pledgor shall
                         ---------------------------
forthwith on demand pay all out-of-pocket expenses incurred by the Pledgee,
including fees and disbursements of its counsel and agents, in connection with
the preparation and administration of this Pledge Agreement or the
administration, sale or other disposition of the Pledged Collateral or the
preservation, protection or defense of the rights of the Pledgee in and to the
Pledged Collateral.  The Pledgor shall forthwith pay on demand the amount of any
taxes which the Pledgee may have been required to pay by reason of the security
interests granted in the Pledged Collateral (including any applicable transfer
taxes) or to free any of the Pledged Collateral from the lien thereof.

          Section 7.4.   Successors and Assigns.  This Pledge Agreement is for
                         ----------------------
the benefit of the Pledgee and its successors and assigns, and in the event of
an assignment of all or any of the Obligations, the rights hereunder, to the
extent applicable to the indebtedness so assigned, may be transferred with such
indebtedness.  This Pledge Agreement shall be binding upon the Pledgor and its
successors and assigns.

          Section 7.5.   Amendments and Waivers.  Any provision of this Pledge
                         ----------------------
Agreement may be amended or waived, if, but only if, such amendment or waiver is
in writing and is signed by the Pledgor and the Pledgee.

          Section 7.6.   Delivery and Virginia Law.  This Pledge Agreement has
                         -------------------------
been delivered in the Commonwealth of Virginia and shall be governed by and
construed in accordance with the laws of the Commonwealth of Virginia, except as
otherwise required by mandatory provisions of law and except to the extent that
remedies provided by the laws of any jurisdiction other than Virginia are
governed by the laws of such jurisdiction.

          Section 7.7.   Limitation by Law; Severability.
                         -------------------------------

          (a)   All rights, remedies and powers provided in this Pledge
Agreement may be exercised only to the extent that the exercise thereof does not
violate any applicable provision of law,

                                     -14-
<PAGE>

and all the provisions of this Pledge Agreement are intended to be subject to
all applicable mandatory provisions of law which may be controlling and be
limited to the extent necessary so that they will not render this Pledge
Agreement invalid, unenforceable in whole or in part, or not entitled to be
recorded, registered or filed under the provisions of any applicable law.

          (b)  If any provision hereof is invalid and unenforceable in any
jurisdiction, then, to the fullest extent permitted by law, (i) the other
provisions hereof shall remain in full force and effect in such jurisdiction and
shall be liberally construed in favor of the Pledgee in order to carry out the
intentions of the parties hereto as nearly as may be possible; and (ii) the
invalidity or unenforceability of any provision hereof in any jurisdiction shall
not affect the validity or enforceability of such provision in any other
jurisdiction.

          Section 7.8.   Counterparts; Effectiveness.  This Pledge Agreement may
                         ---------------------------
be signed in any number of counterparts, each of which shall be an original,
with the same effect as if the signatures thereto and hereto were upon the same
instrument.  This Pledge Agreement shall become effective when the Pledgee shall
have received counterparts hereof signed by itself and the Pledgor.

          IN WITNESS WHEREOF, the parties hereto have caused this Pledge
Agreement to be duly executed by their respective authorized officers as of the
day and year first above written.

Address:  ________________________    ALCANTARA LLC          [SEAL]
          ________________________

                                          /s/ Michael J. Saylor
                                      By: ________________________________
Tax I.D. #: _____________________         Michael J. Saylor, President and
                                          Sole Member

                                      BANK OF AMERICA, N.A.    [SEAL]

Address:  8300 Greensboro Drive, Suite 550
          McLean, Virginia 22102

                                          /s/
                                      By: ________________________________
                                          Name:
                                          Title:



                                     -15-


<PAGE>

                                  Schedule 1
                                  ----------

                               The Listed Assets












                                     -16-
<PAGE>

                                                            EXHIBIT A
                                                            ---------
                           Form of Control Agreement



                                 May 15, 2000


Bank of America, N.A.
730 15th Street, N.W., 6th Floor
Washington, D.C. 20005

Attn: Bradley A. Hughes, Investment Officer

     Re:  Notice of Security Interest in various Securities owned by
          Alcantara LLC and held by Bank of America, N.A., as Manager

Ladies and Gentlemen:

     We are writing on behalf of Bank of America, N.A. as lender (the "Bank")
with regard to the various investment securities held in Account No. 859973
(collectively, the "Account") owned by Alcantara LLC, a Delaware limited
liability company (the "Customer") and held by Bank of America, N.A., Manager
and attorney-in-fact for the Customer (the "Agent").

     The Customer agreed to give to the Bank a security interest in the Account
to induce the Bank to extend and continue credit (the "Credit") to the Customer
and to MicroStrategy Incorporated, a Delaware corporation. As consideration to
induce the Bank to continue to extend such and continue Credit and in order to
secure the payment and performance in full of the Customer's obligations (the
"Obligations") under the documents evidencing and/or securing a portion of the
Credit dated March 26, 1999 and modified May 15, 2000, the Customer has
collaterally assigned and pledged to the Bank, and granted to the Bank a
continuing security interest in all of the Customer's right, title and interest
in and to the Account and all proceeds (cash and non-cash) of the foregoing
(such property being herein referred to as the "Collateral") pursuant to the
terms of and subject to the limitations set forth in a Pledge and Security
Agreement dated May 15, 2000 (the "Pledge Agreement").

     If your firm, as the Agent, is willing to agree to the terms hereof in
order to allow the Customer to use the Collateral for the purposes contemplated
and, therefore, retain the Collateral, please sign the original of this letter
and return it to the undersigned.

     The Agent, by signing this letter, agrees and confirms the following:

     1.  Ownership of the Account shall remain with the Customer.  The
Collateral is held in the Account by the Agent as agent for the Bank alone and,
for the purposes of providing the Bank with a perfected security interest in the
Collateral, possession of the Collateral by the Agent shall be deemed possession
and control thereof by the Bank and not by the Customer. The books and records
of the Agent shall be appropriately marked or amended to reflect the foregoing.
The Agent may, in
<PAGE>

accordance with the Pledge Agreement, register the Collateral at a recognized
securities depository (such as Depository Trust Company), in which event the
Collateral may be registered in the name of the nominee of such depository.

     2.  The Agent agrees that it will comply with entitlement orders and
instructions originated by the Bank with respect to the Account and the
Collateral without the further consent of the Customer.

     3.  Subject to the Agent's authority in Paragraph 1 to register the
Collateral in the name of a nominee or in the name of a depository, the
Collateral shall be held in negotiable and deliverable form.

     4.  All of the Collateral shall remain in the Account at all times during
the term of the Credit. The Bank acknowledges and consents to the receipt by the
Customer of ordinary dividends, distributions or other payments made on account
of the Collateral until the Agent receives written notice from the Bank
specifying that an event of default has occurred under the documents evidencing
and securing the Obligations.

     5.  The Agent will promptly notify the Bank in the event any person
attempts to redeem, cancel, withdraw or grant to any party other than the Bank
any interest in the Collateral or in the event any person or entity obtains or
claims a lien, levy, attachment or other encumbrance against all or any part of
the Collateral.

     6.  The Agent will, upon receipt of a written demand by the Bank, liquidate
such of the Collateral as is specified in such demand, and promptly remit to the
Bank, in immediately available funds payable to the order of the Bank, the
proceeds received therefrom and the Bank and the Customer agree that the Agent
shall be entitled to rely exclusively on the direction of the Bank.

     7.  The Agent will provide to the Bank a copy of each monthly statement
issued by the Agent in connection with the Account.

     The Customer, by its signature below, consents to the Agent acting in
accordance with the agreements set forth herein. The Customer agrees to
indemnify and hold Agent harmless from any and all expenses (including, without
limitation, reasonable attorney's fees) arising from any claims of or
liabilities to the Customer or the Bank or in any way relating to the matters
contemplated hereby. The Bank by its signature below acknowledges that once the
Credit has been paid in full, this letter agreement shall be null and void and
of no further force and effect.

                                                Very truly yours,

                                                BANK OF AMERICA, N.A.


                                                By:__________________________
                                                   Name:
                                                   Title:




                                      -2-
<PAGE>

Acknowledged and Agreed to:

AGENT:

BANK OF AMERICA, N.A.


By:__________________________________
   Name:
   Title:


CUSTOMER:

ALCANTARA LLC


By: _________________________________
    Michael J. Saylor, President
    and Sole Member




                                      -3-
<PAGE>

                                                            EXHIBIT B
                                                            ---------

                             Filing Jurisdictions


Virginia State Corporation Commission
Circuit Court of Fairfax County, Virginia
District of Columbia Recorder of Deeds








                                      -4-