Document:

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                                                                   EXHIBIT 10.22

                         CROSS-INDEMNIFICATION AGREEMENT

        THIS CROSS-INDEMNIFICATION AGREEMENT (this "Agreement"), dated as of
July 1, 2001, is entered into by and among THE ADVISORY BOARD COMPANY (the
"Company"), DAVID G. BRADLEY (the "Selling Stockholder"), JEFFREY D. ZIENTS and
MICHAEL D'AMATO (each of the Selling Stockholder, Mr. Zients and Mr. D'Amato, a
"Stockholder" and collectively, the "Stockholders").

                                    RECITALS:

        WHEREAS, the Stockholders own all of the outstanding shares of the
Company's capital stock (the "Common Stock"); and

        WHEREAS, the Company has elected to be taxed as an S Corporation under
the Code; and

        WHEREAS, the Stockholders are now contemplating offering and selling
their shares of Common Stock to the public (the "Initial Public Offering"); and

        WHEREAS, the Company plans, effective prior to the closing of the
Initial Public Offering, to terminate its S Corporation election (the
"Termination Date"); and

        WHEREAS, after the Termination Date, the Stockholders separately will
continue to be liable for their own federal, state, and local income taxes on
the Company's Tax Items that pass through to the Stockholders under the
provisions of Subchapter S of the Code and any similar provisions of state and
local law for all periods prior to the time the Company ceases to be an S
Corporation, and the Company will be subject to a corporate level tax under
Subchapter C of the Code and certain state and local taxing statutes for periods
thereafter; and

        WHEREAS, the purpose of this Agreement is to set forth the agreement of
the Company and the Stockholders with respect to certain adjustments to the
federal, state and local personal income tax liability of the Stockholders
attributable to Tax Items of the Company that pass through to the Stockholders
under the provisions of Subchapter S of the Code and any similar provisions of
state and local law for periods during which the Company is an S Corporation;

        NOW, THEREFORE, for good and valuable consideration, the receipt and
legal sufficiency of which are hereby acknowledged, the parties agree as
follows:

                                    ARTICLE I
                                   DEFINITIONS

        Section 1.1  For purposes of this Agreement the following definitions
shall apply:

        "Accounting Firm" is defined in Section 4.1.

        "Adjustment" shall mean any final change in any Tax Item initiated by
the IRS, state or local taxing authority or any other relevant taxing authority.
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        "Agreement" is defined in the preamble.

        "C Corporation" shall mean an "C corporation" within the meaning of
Section 1361 of the Code and any similar provisions of state and local law.

        "C Corporation Tax Benefit" shall mean a Tax Benefit of the Company with
respect to any Post-Closing Period.

        "C Corporation Tax Detriment" shall mean a Tax Detriment of the Company
with respect to any Post-Closing Period.

        "Code" shall mean the Internal Revenue Code of 1986, as amended and in
effect for the taxable period in question.

        "Common Stock" is defined in the recitals.

        "Company" is defined in the preamble.

        "Final Determination" shall mean the final resolution of any Income Tax
liability (including all related interest and penalties) for a taxable period. A
Final Determination shall result from the first to occur of:

               (i)     the expiration of thirty (30) days after IRS acceptance
        of a Waiver, unless, within such period, the taxpayer gives notice to
        the other party of the taxpayer's intention to attempt to recover all or
        part of any amount paid pursuant to the Waiver by the filing of a timely
        claim for refund;

               (ii)    a decision, judgment, decree or other order by a court of
        competent jurisdiction that is not subject to further judicial review
        (by appeal or otherwise) and has become final;

               (iii)   the execution of a closing agreement under section 7121
        of the Code or the acceptance by the IRS or its counsel of an offer in
        compromise under section 7122 of the Code or comparable agreements under
        the laws of other jurisdictions;

               (iv)    the expiration of the time for filing a claim for refund
        or for instituting suit in respect of a claim for refund disallowed in
        whole or part by the IRS or other relevant taxing authority;

               (v)     any other final disposition of the tax liability for such
        period by reason of the expiration of the applicable statute of
        limitations; or

               (vi)    any other event that the parties agree is a final and
        irrevocable determination of the liability at issue.

        "Income Tax" shall mean federal income taxes and state and local taxes
imposed upon, or measured by, income. Income Tax includes interest, penalties,
and related additions to tax.

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        "Indemnitor" is defined in Section 3.2.

        "IRS" shall mean the United States Internal Revenue Service or any
successor, including, but not limited to, its agents, representatives and
attorneys.

        "Party" shall mean the Company, the Selling Stockholder, Mr. Zients or
Mr. D'Amato (as the case may be).

        "Pre-Closing Period" shall mean any taxable period ending on or prior to
the Termination Date.

        "Pro Rata Share" shall mean each Stockholder's proportionate share of
Common Stock owned on the relevant date or held during the relevant period,
which proportionate share shall be determined based on, among other things, (i)
the number of shares of Common Stock held by the Stockholder on the relevant
date or during the relevant period in comparison to the number of shares of
Common Stock held by all Stockholders as of the relevant date or during the
relevant period, and (ii) whether, and the extent to which, the Stockholder held
shares of Common Stock on the relevant date or during the relevant period.

        "Post-Closing Period" shall mean any taxable period that is not a
Pre-Closing Period.

        "S Corporation" shall mean an "S corporation" within the meaning of
Section 1361 of the Code and any similar provisions of state and local law.

        "S Corporation Tax Benefit" shall mean the aggregate Tax Benefit of the
Stockholders resulting from an Adjustment to a Tax Item of the Company with
respect to any Pre-Closing Period.

        "S Corporation Tax Detriment" shall mean the aggregate Tax Detriment of
the Stockholders resulting from an Adjustment to a Tax Item of the Company with
respect to any Pre-Closing Period.

        "Selling Stockholder" is defined in the preamble.

        "Stockholder" and "Stockholders" are defined in the preamble.

        "Tax Benefit" shall mean any decrease in the Income Tax liability of a
Party for any taxable period as a result of an Adjustment. An Adjustment shall
be deemed to result in a Tax Benefit to a Party only if, when and to the extent
that such Party's Income Tax liability for a taxable period is less than it
would have been if such liability were determined without regard to such
Adjustment.

        "Tax Detriment" shall mean any increase in the Income Tax liability of a
Party for any taxable period as a result of an Adjustment. An Adjustment shall
be deemed to result in a Tax Detriment to a Party only if, when and to the
extent that such Party's Income Tax liability for a taxable period is greater
than it would have been if such liability were determined without regard to such
Adjustment.

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        "Tax Item" shall mean any tax item (including, but not limited to, items
of income, gain, loss, deduction, credit, recapture of credit, basis or adjusted
basis) which affects the Income Taxes paid or payable by a Party.

        "Termination Date" is defined in the recitals.

        "Waiver" shall mean a Waiver of Restrictions on Assessment and
Collection of Deficiency in Tax and Acceptance of Overassessment on Federal
Revenue Form 870 or 870-AD (or any successor comparable form or the expiration
of a comparable period with respect to any comparable agreement or form under
the laws of other jurisdictions).

                                   ARTICLE II
                        INDEMNIFICATION FOR CERTAIN TAXES

        Section 2.1   If, based on a Final Determination, the Company is deemed
to have been a C Corporation during any Pre-Closing Period, each Stockholder
severally, but not jointly, agrees to contribute to the capital of the Company
its Pro Rata Share of the amount necessary to hold the Company harmless from any
Income Taxes (net of any refunds) arising from such Final Determination.
Notwithstanding the foregoing, each Stockholder's obligation under this Section
2.1 shall be limited to the total distributions to the Stockholder made by the
Company through and including the Termination Date, reduced by any Income Taxes
(net of any refunds) of the Stockholders attributable to such distributions.

        Section 2.2   If there is an Adjustment with respect to a Tax Item of
the Company which results in an S Corporation Tax Detriment and a corresponding
C Corporation Tax Benefit, the Company shall pay to the Stockholders in
proportion to their relative Tax Detriments (which collectively gave rise to the
S Corporation Tax Detriment) an amount equal to the lesser of (i) such S
Corporation Tax Detriment and (ii) such C Corporation Tax Benefit.

        Section 2.3   If there is an Adjustment with respect to a Tax Item of
the Company which results in an C Corporation Tax Detriment and a corresponding
S Corporation Tax Benefit, each Stockholder severally, but not jointly, shall
pay to the Company in proportion to their relative Tax Benefits (which
collectively gave rise to the S Corporation Tax Benefit) an amount equal to the
lesser of (i) such C Corporation Tax Detriment and (ii) such S Corporation Tax
Benefit.

        Section 2.4   Each Party must take all reasonable steps to secure in a
timely manner any Tax Benefit to which they are entitled and which corresponds
to a Tax Detriment covered by Sections 2.2 or 2.3 above.

        Section 2.5   Any payment required under this Article II shall be made
within thirty (30) days after the date on which both the Tax Detriment and the
corresponding Tax Benefit (as covered by Sections 2.2 or 2.3 above,
respectively) have been recognized by the Parties except, if the Parties are
unable to agree that such payment is due, such payment shall be made within
thirty (30) days after a determination regarding such payment is made by the
Accounting Firm pursuant to the procedures set forth in Article IV.
Notwithstanding the foregoing, in the case of a deferred Tax Benefit which may
be reasonably measured and calculated and which there is a reasonable
expectation of recognition by the benefited Party, the Parties agree to deem
such

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deferred Tax Benefit as currently recognized in an amount equal to the present
value of such deferred Tax Benefit for purposes of any payment required under
this Article II.

                                   ARTICLE III
              TAX FILINGS, COOPERATION AND EXCHANGE OF INFORMATION

        Section 3.1   With respect to any Pre-Closing Period, Arthur Andersen
LLP (or such other accounting firm as the Stockholders and the Company shall
mutually agree to in writing) shall prepare and file all tax returns of the
Company for such taxable periods under the direction of the Stockholders. The
Company shall be permitted to review and comment on each such tax return
described in the preceding sentence prior to filing and to make revisions to
such tax returns as the Parties agree after full, good faith consultation, or
pursuant to the dispute resolution provisions set forth in Article IV hereof.

        Section 3.2   Whenever a Party becomes aware of an issue which could
give rise to payment or indemnification from the other Party under Article II,
such Party shall promptly give notice of the issue to the other Party (the
"Indemnitor"). The Indemnitor and its representatives, at the Indemnitor's
expense, shall be entitled to participate in all conferences, meetings or
proceedings with the IRS or other taxing authority with respect to the issue. If
the Indemnitor is more than one Stockholder, the Selling Stockholder shall
participate in such conferences, meetings and proceedings with the Company, the
IRS or the applicable taxing authority on behalf of all Stockholders.

        Section 3.3   The Parties agree to consult and cooperate fully with each
other, as and to the extent reasonably requested by the other Party, in
connection with the preparation and filing of any tax returns pursuant to this
Article III and the audit, negotiation, settlement or litigation of any
Adjustment that may give rise to any payment or an indemnification obligation
under this Agreement. Such cooperation shall include the retention and (upon the
other Party's request) the provision of records and information which are
reasonably relevant to any such filing, audit, negotiation, settlement or
litigation and making employees available on a mutually convenient basis to
provide additional information and explanation of any material provided
hereunder. All decisions with respect to such filing, audit, negotiation,
settlement or litigation shall be made by the Parties after full, good faith
consultation or pursuant to the dispute resolution provisions set forth in
Article IV hereof. Notwithstanding anything in this Article III to the contrary,
the Stockholders, in their sole discretion, may elect to direct and control, at
their own expense, any audit, negotiation, settlement or litigation of any issue
which could give rise to payment or indemnification from the Stockholders under
Article II or otherwise adversely affect the Stockholders; provided, however, no
final decision with respect to such audit, negotiation, settlement or litigation
shall be made by the Stockholders without first complying with the provisions of
the preceding sentence.

        Section 3.4   The Company agrees (i) to retain all books and records for
any Pre-Closing Period in which the Company was taxable as an S Corporation
until the expiration of the applicable statute of limitations (and, to the
extent notified by the Stockholders, any extensions thereof), and (ii) to give
the Stockholders reasonable written notice prior to transferring, destroying or
discarding any such books and records and, if the Stockholders so request, they
shall be allowed to take possession of such books and records.

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        Section 3.5   The Company shall not amend any Pre-Closing Period tax
return of the Company without the prior written consent of the Stockholders, and
shall not take a position with respect to a Tax Item of the Company reflected on
any Post-Closing Period tax return of the Company that is inconsistent with a
position taken on a Pre-Closing Period tax return of the Company unless the
Company either receives the prior written consent of the Selling Stockholder or
such position will not result in an S Corporation Tax Detriment.

                                   ARTICLE IV
                                    DISPUTES

        Section 4.1   If the Parties are, after negotiation in good faith,
unable to agree upon the appropriate application of this Agreement, the
controversy shall be settled by the accounting firm (the "Accounting Firm")
remaining on the list of firms set forth on Schedule A hereto after the Company
and the Selling Stockholder, commencing with the Selling Stockholder, shall have
objected seriatim to the other firms on the list. The decision of the Accounting
Firm shall be final, and each of the Company and the Stockholders agree
immediately to pay to the other any amount due under this Agreement pursuant to
such decision or otherwise follow the decision or instructions of the Accounting
Firm. The expenses of the Accounting Firm shall be borne one-half by the Company
and one-half by the Stockholders (on a Pro Rata Share basis), unless the
Accounting Firm specifies otherwise.

                                    ARTICLE V
                                  MISCELLANEOUS

        Section 5.1   Term of Agreement. This Agreement shall become effective
as of the date of its execution and shall continue in full force and effect
indefinitely.

        Section 5.2   Severability. If any term of this Agreement is held by a
court of competent jurisdiction to be unenforceable, the remainder of the terms
set forth herein shall remain in full force and effect and shall in no way be
impaired. The Parties stipulate that they would have executed the remaining
terms without including any which may hereafter be declared unenforceable. In
the event that any term is held to be unenforceable, the Parties shall use their
best efforts to find an alternative means to achieve the same or substantially
the same result as that contemplated by such term.

        Section 5.3   Assignment. Except by operation of law or in connection
with the sale of all or substantially all the assets of the Company, this
Agreement shall not be assignable, in whole or in part, directly or indirectly,
by one Party without the prior written consent of the other Parties. Any attempt
to assign any right or obligations arising under this Agreement without such
consent shall be void. However, the provisions of this Agreement shall be
binding upon, inure to the benefit of and be enforceable by the Parties and
their respective successors and permitted assigns.

        Section 5.4   Further Assurances. Subject to the provisions of this
Agreement, the parties shall acknowledge such other instruments and documents,
and take all other actions, as may be reasonably required in order to effectuate
the purposes of this Agreement.

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        Section 5.5   Parties in Interest. Except as herein otherwise
specifically provided, nothing in this Agreement expressed or implied is
intended to confer any right or benefit upon any person, firm or corporation
other than the Parties and their respective successors and permitted assigns.

        Section 5.6   Waivers, Etc. No failure or delay on the part of any Party
in exercising any power or right under this Agreement shall operate as a waiver
thereof, nor shall any single or partial exercise of any such right or power, or
any abandonment or discontinuance of steps to enforce such right or power,
preclude any other or further exercise thereof or the exercise of any other
right or power. No modification or waiver of any provision of this Agreement nor
consent to any departure by any party therefrom shall in any event be effective
unless it shall be in writing, and then such waiver or consent shall be
effective only in the specific instance and for the purpose which given.

        Section 5.7   Set-off. All payments to be made by any Party under this
Agreement shall be made without set-off, counterclaim or withholding, all of
which are expressly waived.

        Section 5.8   Change of Law. If, due to any change in applicable law or
regulation or the interpretation thereof by any court or other governing body
having jurisdiction subsequent to the date of this Agreement, performance of any
provision of this Agreement shall be impracticable or impossible, the Parties
shall use their best efforts to find alternative means to achieve the same or
substantially the same results as are contemplated by such provision.

        Section 5.9   Headings. Descriptive headings are for convenience only
and shall not control or affect the meaning of any provision of this Agreement.

        Section 5.10  Counterparts. For the convenience of the Parties, any
number of counterparts of this Agreement may be executed by the Parties and each
executed counterpart shall be an original instrument.

        Section 5.11  Notices. All notices provided for in this Agreement shall
be validly given if in writing and (i) delivered personally or (ii) sent by
registered mail, postage prepaid, return receipt registered to the address set
forth below:

        If to the Company:

               The Advisory Board Company
               The Watergate
               600 New Hampshire Avenue, N.W.
               Washington, D.C.  20037
               Attn.: David Felsenthal

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        If to the Stockholders:

               c/o The Advisory Board Company
               The Watergate
               600 New Hampshire Avenue, N.W.
               Washington, D.C.  20037
               Attn.: David Felsenthal

or to such other address as the parties may, from time to time, designate in a
written notice given in a like manner to the other parties hereto. Notice given
in person shall be deemed delivered when received (or when delivery is first
refused) and notice given by mail shall be deemed delivered five (5) calendar
days after the date mailed.

        Section 5.12  Governing Law. This Agreement shall be governed by the
domestic substantive laws of the State of Delaware without regard to any choice
or conflict of laws rule or provision that would cause the application of the
domestic substantive laws of any other jurisdiction.

                            [Signature page follows.]

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        IN WITNESS WHEREOF, the undersigned have caused this
Cross-Indemnification Agreement to be duly executed as of the day and year first
written above.

                                            The Advisory Board Company

                                            By:    /s/ FRANK WILLIAMS
                                                   -----------------------------
                                            Name:  Frank Williams
                                            Title: Chief Executive Officer

                                            /s/ DAVID G. BRADLEY
                                            ------------------------------------
                                            David G. Bradley

                                            /s/ JEFFREY D. ZIENTS
                                            ------------------------------------
                                            Jeffrey D. Zients

                                            /s/ MICHAEL D'AMATO
                                            ------------------------------------
                                            Michael D'Amato

                                       9<PAGE>   1
                                                                   EXHIBIT 10.23

                                 PROMISSORY NOTE

$7,500,000                                                     December 21, 1999

        FOR VALUE RECEIVED, the undersigned, the Advisory Beard Company, a
Maryland corporation with its place of business at 600 New Hampshire Avenue,
N.W., Washington, D.C., 20037, promises to pay to order of David G. Bradley, an
individual with his principal residence at 2211 30th Street, N.W., Washington,
D.C., 20008, the principal sum of $7,500,000, with interest at the rate of seven
percent (7%) per annum, subject to the terms and conditions herein contained.

        1.      The principal sum shall be due and payable on December 21, 2000.

        2.      Interest on the outstanding balance of the principal sum shall
accrue at the rate of seven percent (7%) per annum from December 21, 1999 until
this Note is paid in full, and shall include an interim interest payment on July
1, 2000.

        3.      This Note may be prepaid in whole or in part at any time without
penalty.

        4.      This Note is secured by the cash, marketable securities, and
membership fees receivable of the Advisory Board Company.

        5.      Upon the occurrence of an Event of Default, as that term is
defined below, and the continuation of any such Event of Default for a period of
thirty days after the delivery of written notice to the undersigned setting
forth such Event of Default, the unpaid balance of the principal and any
interest accrued thereon shall, at the option of the holder hereof, at once
become due and payable. The notice of default shall be deemed to be delivered if
delivered to the undersigned or if sent by United States certified or registered
mail to the undersigned at the address set forth above or at the last address
furnished by it for such purpose.

        An Event of Default will be deemed to have occurred upon the happening
of any of the following events:

                (a)     Debtor fails to pay the principal payments and accrued
interest when due in accordance with the Note.

                (b)     Debtor files a voluntary proceeding under the Bankruptcy
Code, or any involuntary petitions under the Bankruptcy Code are filed against
the Debtor.

                (c)     Any lien or other attachment is placed against the
Collateral (other than the security interest created hereby) or a Writ of
Execution is served against the Collateral.

        6.      Any payment by the undersigned on this Note shall be credited
first to any interest then due, and the remainder on the principal sum, and
interest shall thereupon cease to accrue upon the amount so credited on the said
principal sum.

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        7.      All installments of principal and interest hereunder shall be
payable in lawful money of the United States.

IN WITNESS WHEREOF, the undersigned has set its hand and seal as of the day,
month and year first hereinabove written.

Debtor:
The Advisory Board Company, Inc.

/s/Jeffrey D. Zients                              12/21/99
-------------------------------                   ----------------------------
Jeffrey D. Zients, President                      Date

Creditor:
/s/David G. Bradley                               December 28, '99
-------------------------------                   -----------------------------
David G. Bradley                                  Date

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