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                                  EXHIBIT 10.28

                               SECURITY AGREEMENT

      THIS SECURITY AGREEMENT, dated as of April 18, 2000, is made by PRIME
GROUP OUTDOOR, LLC, a Delaware limited liability company ("Grantor"), in favor
of HORIZON GROUP PROPERTIES, L.P. ("Lender").

                             W I T N E S S E T H:

      A. Pursuant to a certain Promissory Note dated as of even date herewith in
the principal amount of One Million, Five Hundred Thousand Dollars ($1,500,000)
(the "Note"), Lender has agreed to make a loan (the "Loan"), to Grantor in the
principal amount of the Note.

      B. Lender has required, as a condition to making the Loan, that Grantor
execute and deliver this Security Agreement to Lender, in order to secure its
obligations hereunder, under the Note and under any document, instrument or
agreement executed and delivered in connection with the Note (collectively, the
"Obligations").

      NOW, THEREFORE, in consideration of the premises and of the mutual
covenants herein contained and for other good and valuable consideration, the
receipt of which is hereby acknowledged, the parties hereto agree as follows:

      1. DEFINED TERMS. The following terms shall have the following meanings
(such meanings being equally applicable to both the singular and plural forms of
the terms defined):

            "ACCOUNT DEBTOR" shall mean any "account debtor," as such term is
      defined in section 9-105(1)(a) of the UCC.

            "ACCOUNTS RECEIVABLE" shall mean any "account," as such term is
      defined in section 9-106 of the UCC, now owned or hereafter acquired by
      Grantor and, in any event, shall include, without limitation, all
      accounts, accounts receivable, other receivables, contract rights, chattel
      paper, instruments, documents, notes, and other forms of obligations now
      owned or hereafter received or acquired by or belonging or owing to
      Grantor (including, without limitation, under any trade names, styles or
      divisions thereof) whether arising out of goods sold or services rendered
      by Grantor or from any other transaction, whether or not the same involves
      the sale of goods or services by Grantor (including, without limitation,
      any such obligation which might be characterized as an account or contract
      right under the UCC) and all of Grantor's rights in, to and under all
      purchase orders or receipts now owned or hereafter acquired by it for
      goods or services, and all of Grantor's rights to any goods represented by
      any of the foregoing (including, without limitation, unpaid seller's
      rights of rescission, replevin, reclamation and stoppage in transit and
      rights to returned, reclaimed or repossessed goods), and all moneys due or
      to become due to Grantor under all contracts for the sale of goods or the
      performance of services or both by Grantor (whether or not yet earned by
      performance on the part of Grantor or in connection with any other
      transaction), now in existence or hereafter occurring, including, without
      limitation, the right to receive the proceeds of said purchase orders and
      contracts, and all collateral security and guarantees of any kind given by
      any person with respect to any of the foregoing.

            "CHATTEL PAPER" shall mean any "chattel paper," as such term is
      defined in section 9-105(1)(b) of the UCC, now owned or hereafter acquired
      by Grantor.

            "COLLATERAL" shall have the meaning assigned to such term in Section
      2 of this Security Agreement.

            "CONTRACTS" shall mean all contracts, undertakings, or other
      agreements (other than rights


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      evidenced by Chattel Paper, Documents or Instruments) in or under which
      Grantor may now or hereafter have any right, title or interest, including,
      without limitation, with respect to an Account, any agreement relating to
      the terms of payment or the terms of performance thereof.

            "DOCUMENTS" shall mean any "documents," as such term is defined in
      section 9-105(1)(f) of the UCC, now owned or hereafter acquired by
      Grantor.

            "EQUIPMENT" shall mean any "equipment," as such term is defined in
      section 9-109(2) of the UCC, now owned or hereafter acquired by Grantor
      and, in any event, shall include, without limitation, all machinery,
      equipment, furnishings, fixtures, vehicles and computers and other
      electronic data-processing and other office equipment now owned or
      hereafter acquired by Grantor and any and all additions, substitutions and
      replacements of any of the foregoing, wherever located, together with all
      attachments, components, parts, equipment and accessories installed
      thereon or affixed thereto.

            "EVENT OF DEFAULT" shall have the meaning set forth in Section 9.

            "INSTRUMENTS" shall mean any "instrument," as such term is defined
      in section 9-105(1)(i) of the UCC, now owned or hereafter acquired by
      Grantor, other than instruments that constitute, or are a part of a group
      of writings that constitute, Chattel Paper.

            "INTANGIBLE ASSETS" shall mean any "general intangibles," as such
      term is defined in section 9-106 of the UCC, now owned or hereafter
      acquired by Grantor and, in any event, shall include, without limitation,
      all right, title and interest which Grantor may now or hereafter have in
      or under any Contract, all customer lists, trademarks, patents, rights in
      intellectual property, licenses, permits, copyrights, trade secrets,
      proprietary or confidential information, inventions (whether patented or
      patentable or not), technical information, procedures, designs, knowledge,
      know-how, software, data bases, data, skill, expertise, experience,
      processes, models, drawings, materials and records now owned or hereafter
      acquired by Grantor, goodwill and rights of indemnification.

            "INVENTORY" shall mean any "inventory," as such term is defined in
      section 9-109(4) of the UCC, now owned or hereafter acquired by Grantor
      and, in any event, shall include, without limitation, all inventory,
      merchandise, goods and other personal property now owned or hereafter
      acquired by Grantor which are held for sale or lease or are furnished or
      are to be furnished under a contract of service or which constitute raw
      materials, work in process or materials used or consumed or to be used or
      consumed in Grantor's business, or the processing, packaging, delivery or
      shipping of the same, and all finished goods.

            "INVESTMENT PROPERTY" shall mean all "investment property" as such
      term is defined in the UCC, now or hereafter owned or acquired by,
      Grantor, wherever located and, in any event, including, without
      limitation, (a) stocks, bonds, interests in limited liability companies,
      partnership interests, treasuries, certificates of deposit and mutual fund
      shares; (b) all securities entitlements of Grantor, including, without
      limitation, all rights of Grantor to any securities account and any free
      credit balance or other money owing by any securities intermediary with
      respect to any such account; (c) all securities accounts held by Grantor;
      (d) all commodity contracts held by Grantor; and (e) all commodity
      accounts held by Grantor.

            "NOTE" shall have the meaning set forth in the Recitals.

            "OBLIGATIONS" shall have the meaning set forth in the Recitals.

            "PROCEEDS" shall mean "proceeds," as such term is defined in section
      9-306(1) of the UCC and, in any event, shall include, without limitation,
      (i) any and all proceeds of any insurance, indemnity, warranty or guaranty
      payable to Grantor from time to time with respect to any of the
      Collateral, (ii) any and all


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      payments (in any form whatsoever) made or due and payable to Grantor from
      time to time in connection with any requisition, confiscation,
      condemnation, seizure or forfeiture of all or any part of the Collateral
      by any governmental body, authority, bureau or agency (or any person
      acting under color of governmental authority), (iii) any claim of Grantor
      against third parties (A) for past, present or future infringement of any
      patent or patent license or (B) for past, present or future infringement
      or dilution of any trademark or trademark license or for injury to the
      goodwill associated with any trademark, trademark registration or
      trademark licensed under any trademark license, and (iv) any and all other
      amounts from time to time paid or payable under or in connection with any
      of the Collateral.

            "SECURITY AGREEMENT" shall mean this Security Agreement, as the same
      may from time to time be amended, modified or supplemented and shall refer
      to this Security Agreement as in effect of the date such reference becomes
      operative.

            "UCC" shall mean the Uniform Commercial Code as the same may, from
      time to time, be in effect in the State of Illinois; PROVIDED, HOWEVER, in
      the event that, by reason of mandatory provisions of law, any or all of
      the attachment, perfection or priority of Lender's security interest in
      any Collateral is governed by the Uniform Commercial Code as in effect in
      a jurisdiction other than the State of Illinois, the term "UCC" shall mean
      the Uniform Commercial Code as in effect in such other jurisdiction for
      purposes of the provisions hereof relating to such attachment, perfection
      or priority and for purposes of definitions related to such provisions.

      2.    GRANT OF SECURITY INTEREST.

            (a) As collateral security for the prompt and complete payment and
      performance when due (whether at stated maturity, by acceleration or
      otherwise) of the Obligations, Grantor hereby assigns, conveys, mortgages,
      pledges, hypothecates and transfers to Lender, and hereby grants to
      Lender, a security interest in, all of Grantor's right, title and interest
      in, to and under the following (all of which being hereinafter
      collectively called the "Collateral"):

               (i)      all Accounts Receivable of Grantor;

              (ii)      all Chattel Paper of Grantor;

             (iii)      all Contracts of Grantor;

              (iv)      all Documents of Grantor;

               (v)      all Equipment of Grantor;

              (vi)      all Intangible Assets of Grantor;

             (vii)      all Instruments of Grantor;

            (viii)      all Inventory of Grantor;

              (ix)      all Investment Property of Grantor;

               (x)      to the extent not otherwise included, all Proceeds of
                        each of the foregoing and all accessions to,
                        substitutions and replacements for, and rents, profits
                        and product of each of the foregoing.


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            (b) In addition, as collateral security for the prompt and complete
      payment when due of the Obligations and in order to induce Lender as
      aforesaid, Lender is hereby granted a lien and security interest in all
      property of Grantor held by Lender, including, without limitation, all
      property of every description, now or hereafter in the possession or
      custody of or in transit to Lender for any purpose, including safekeeping,
      collection or pledge, for the account of Grantor, or as to which Grantor
      may have any right or power.

            (c) The Collateral shall not include any assets of Grantor in which
      Grantor has granted Old National Bank a security interest pursuant to that
      certain Commercial Security Agreement dated April 14, 2000 between Grantor
      and Old National Bank, which Grantor represents and warrants consist
      solely of the assets described on EXHIBIT A attached hereto, to the extent
      that a breach of or a default under such Commercial Security Agreement
      would result by including any such assets within the definition of the
      Collateral.

      3. RIGHTS OF LENDER; LIMITATIONS ON LENDER'S OBLIGATIONS.

            (a) It is expressly agreed by Grantor that, anything herein to the
      contrary notwithstanding, Grantor shall remain liable under each of its
      Contracts to observe and perform all the conditions and obligations to be
      observed and performed by it thereunder and Grantor shall perform all of
      its duties and obligations thereunder, all in accordance with and pursuant
      to the terms and provisions of each such Contract. Lender shall not have
      any obligation or liability under any Contract by reason of or arising out
      of this Security Agreement or the granting to Lender of a security
      interest therein or the receipt by Lender of any payment relating to any
      Contract pursuant hereto, nor shall Lender be required or obligated in any
      manner to perform or fulfill any of the obligations of Grantor under or
      pursuant to any Contract, or to make any payment, or to make any inquiry
      as to the nature or the sufficiency of any payment received by it or the
      sufficiency of any performance by any party under any Contract, or to
      present or file any claim, or to take any action to collect or enforce any
      performance or the payment of any amounts which may have been assigned to
      it or to which it may be entitled at any time or times.

            (b) Grantor hereby authorizes Lender, at any time or times after the
      occurrence and during the continuance of an Event of Default, to (i)
      notify any or all Account Debtors that the Accounts Receivable have been
      assigned to Lender and that Lender has a security interest therein and
      (ii) direct such Account Debtors to make all payments due from them to
      Grantor upon the Accounts Receivable directly to Lender or to a lock box
      designated by Lender. Lender shall promptly furnish Grantor with a copy of
      any such notice sent. Any such notice, in Lender's sole discretion, may be
      sent on Grantor's stationery, in which event Grantor shall co-sign such
      notice with Lender.

            (c) Lender shall have the right to make test verifications of the
      Accounts Receivable in any manner and through any commercially reasonable
      medium that it considers advisable, and Grantor agrees to furnish all such
      assistance and information as Lender may require in connection therewith.
      Grantor at its expense will cause certified independent public accountants
      satisfactory to Lender to prepare and deliver to Lender at any time and
      from time to time promptly upon Lender's request, the following reports:
      (i) a reconciliation of all its Accounts Receivable, (ii) an aging of all
      its Accounts Receivable, (iii) trial balances, and (iv) a test
      verification of such Accounts Receivable as Lender may request.

      4. REPRESENTATIONS AND WARRANTIES. Grantor hereby represents and warrants
that:

            (a) Except for the security interest granted to Lender pursuant to
      this Security Agreement, Grantor is the sole owner of each item of the
      Collateral in which it purports to grant a security interest hereunder,
      having good and marketable title thereto, free and clear of any and all
      liens and encumbrances. No material amounts payable under or in connection
      with any of its Accounts Receivable or Contracts are


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      evidenced by Instruments which have not been delivered to Lender.

            (b) No effective security agreement, financing statement, equivalent
      security or lien instrument or continuation statement covering all or any
      part of the Collateral has been executed by Grantor or is on file or of
      record in any public office, except such as may have been filed by Grantor
      in favor of Lender pursuant to this Security Agreement.

            (c) Upon the filing of appropriate financing statements, this
      Security Agreement shall be effective to create a valid and continuing
      first priority lien on and first priority perfected security interest in
      the Collateral with respect to which a security interest may be perfected
      by filing pursuant to the UCC in favor of Lender prior to all other liens,
      and is enforceable as such as against creditors of and purchasers from
      Grantor. All action necessary or desirable to protect and perfect such
      security interest in each item of the Collateral has been duly taken.

            (d) Grantor's principal place of business and the place where its
      records concerning the Collateral are kept is located at the address of
      Grantor set forth in Section 12 hereof, and Grantor will not change such
      principal place of business or remove such records unless it has taken
      such action as is necessary to cause the security interest of Lender in
      the Collateral to continue to be perfected. Grantor will not change its
      principal place of business or the place where its records concerning the
      Collateral is kept without giving thirty (30) days' prior written notice
      thereof to Lender.

            (e) Grantor is a limited liability company, duly formed, validly
      existing and in good standing under the laws of the State of Delaware;
      Grantor is properly qualified to do business and is in good standing under
      the laws of each state in which it either owns property or transacts
      business; the execution, delivery and performance of this Security
      Agreement, the Note and all other related documents and agreements have
      been authorized by all necessary actions of Grantor's Board of Managers
      and member; the Note, this Agreement and all other related documents and
      agreements have been duly executed and delivered by Grantor and constitute
      the legal, valid and binding obligations of Grantor enforceable in
      accordance with their respective terms.

            (f) Grantor is the owner of all assets and property relating to the
      outdoor billboard advertising business described in that certain Business
      Plan of Prime Outdoor Group prepared by Mark Harris and Gina Crist; a
      true, correct and complete list of all of Grantor's assets is attached
      hereto as Exhibit B.

            (g) Neither the execution, delivery and performance of the Note or
      this Security Agreement, nor the exercise of Lender's rights and remedies
      thereunder or hereunder, shall violate, conflict with, breach or cause a
      default under any document, instrument or agreement applicable to or
      relating to Grantor or any portion of the Collateral or to which Borrower
      is a party or by which it is bound.

      5. COVENANTS. Grantor covenants and agrees with Lender that from and after
the date of this Security Agreement and until the Obligations are fully
satisfied:

            (a) FINANCING STATEMENTS AND FURTHER DOCUMENTATION. Grantor will
      join with Lender in the execution and filing of such financing statement
      or statements in the form and content reasonably required by Lender.
      Grantor will pay all costs of filing any financing, continuation or
      termination statements with respect to the security interest created by
      this Agreement, together with costs and expenses of any lien search
      required by Lender, during the term hereof, either as a condition
      precedent to the extension of the Loan or as a condition precedent to any
      advance made by Lender to Grantor hereunder. At any time and from time to
      time, upon the written request of Lender, and at the sole expense of
      Grantor, Grantor will promptly and duly execute and deliver any and all
      such further instruments and documents and


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      take such further action as Lender may reasonably deem desirable to obtain
      the full benefits of this Security Agreement and of the rights and powers
      herein granted, including, without limitation, using its best efforts to
      secure all consents and approvals necessary or appropriate for the
      assignment to Lender of any Contract held by Grantor or in which Grantor
      has any rights not heretofore assigned, the filing of any financing or
      continuation statements under the UCC with respect to the liens and
      security interests granted hereby, transferring Collateral to the Lender's
      possession (if a security interest in such Collateral can be perfected by
      possession), placing the interest of Lender as lienholder on the
      certificate of title of any vehicle and using its best efforts to obtain
      waivers of liens from landlords and mortgagees. Grantor also hereby
      authorizes Lender to file any such financing or continuation statement
      without the signature of Grantor to the extent permitted by applicable
      law.

            (b) SPECIAL COLLATERAL. Immediately upon Grantor's receipt of that
      portion of the Collateral which is or becomes evidenced by an agreement,
      instrument and/or document, including, without limitation, promissory
      notes, trade acceptances, documents of title and warehouse receipts (the
      "Special Collateral"), Grantor shall deliver the original thereof to
      Lender, together with appropriate endorsements or other specific evidence
      (in form and substance reasonably acceptable to Lender) of assignment
      thereof to Lender.

            (c) MAINTENANCE OF RECORDS. Grantor will keep and maintain at its
      own cost and expense satisfactory and complete records of the Collateral,
      including, without limitation, a record of all payments received and all
      credits granted with respect to the Collateral and all other dealings with
      the Collateral. Grantor will mark its books and records pertaining to the
      Collateral to evidence this Security Agreement and the security interests
      granted hereby. All Chattel Paper will be marked with the following
      legend: "This writing and the obligations evidenced or secured hereby are
      subject to the security interest of Horizon Group Properties, Inc. (or any
      successor lender)". For Lender's further security, Grantor agrees that
      Lender shall have a special property interest in all of Grantor's books
      and records pertaining to the Collateral and, upon the occurrence and
      during the continuation of any Event of Default, Grantor shall deliver and
      turn over true, correct and complete copies of any such books and records
      to Lender or to its representatives at any time on demand of Lender. Prior
      to the occurrence of an Event of Default and upon reasonable notice from
      Lender, Grantor shall permit any representative of Lender to inspect such
      books and records and will provide photocopies thereof to Lender.

            (d) INDEMNIFICATION. In any suit, proceeding or action brought by
      Lender relating to any Account Receivable, Chattel Paper, Contract,
      Intangible Asset or Instrument for any sum owning thereunder, or to
      enforce any provision of any Account Receivable, Chattel Paper, Contract,
      Intangible Asset or Instrument, Grantor will save, indemnify and keep
      Lender harmless from and against all expense, loss or damage suffered by
      reason of any defense, setoff, counterclaim, recoupment or reduction of
      liability whatsoever of the obligor thereunder, arising out of a breach by
      Grantor of any obligation thereunder or arising out of any other
      agreement, indebtedness or liability at any time owing to, or in favor of,
      such obligor or its successors from Grantor, and all such obligations of
      Grantor shall be and remain enforceable against and only against Grantor
      and shall not be enforceable against Lender.

            (e) COMPLIANCE WITH LAWS, ETC. Grantor will comply, in all material
      respects, with all acts, rules, regulations, orders, decrees and
      directions of any governmental authority, applicable to the Collateral or
      any part thereof or to the operation of Grantor's business; PROVIDED,
      HOWEVER, that Grantor may contest any act, regulation, order, decree or
      direction in any reasonable manner which shall not in the sole opinion of
      Lender, adversely affect Lender's rights hereunder or adversely affect the
      first priority of its security interest in the Collateral.

            (f) PAYMENT OF OBLIGATIONS. Grantor will pay promptly when due all
      charges imposed upon the Collateral or in respect of its income or profits
      therefrom and all claims of any kind (including, without limitation,
      claims for labor, material and supplies).


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            (g) COMPLIANCE WITH TERMS OF ACCOUNTS, ETC. In all material
      respects, Grantor will perform and comply with all obligations in respect
      of Accounts Receivable, Chattel Paper and Contracts and all other
      agreements to which it is a party or by which it is bound.

            (h) LIMITATION ON LIENS ON COLLATERAL. Except for the liens
      previously granted to Old National Bank, Grantor will not create, permit
      or suffer to exist, and will defend the Collateral and any real property
      now or hereafter owned by Grantor against and take such other action as is
      necessary to remove, any lien on the Collateral or any of its real
      property, and will defend the right, title and interest of Lender in and
      to any of Grantor's rights under the Chattel Paper, Contracts, Documents,
      Intangible Assets and Instruments and to the Equipment and Inventory and
      real property and in and to the Proceeds thereof against the claims and
      demands of all persons whomsoever.

            (i) MAINTENANCE OF INSURANCE. Grantor will maintain, with
      financially sound and reputable companies, insurance policies (i) insuring
      its Inventory and Equipment against loss by fire, explosion, theft and
      such other casualties as are usually insured against by companies engaged
      in the same or similar businesses and (ii) insuring Grantor and Lender
      against liability for personal injury and property damage relating to such
      Inventory and Equipment, such policies to be in such amounts and against
      at least such risks as are usually insured against, in the same general
      area by companies engaged in the same or a similar business, naming Lender
      as an additional insured with losses payable to Grantor and Lender, as
      their respective interests may appear, under a standard non-contributory
      "mortgagee", "lender" or "secured party" clause. Grantor shall, if so
      requested by Lender, deliver to Lender as often as Lender may reasonably
      request, a report of a reputable insurance broker satisfactory to Lender
      with respect to the insurance on its Inventory and Equipment. All
      insurance with respect to the Inventory and Equipment shall (i) contain a
      clause which provides that Lender's interest under the policy will not be
      invalidated by any act or omission of, or any breach of warranty by, the
      insured, or by any change in the title, ownership or possession of the
      insured property, or by the use of the property for purposes more
      hazardous than is permitted in the policy, and (ii) provide that no
      cancellation, reduction in amount or change in coverage thereof shall be
      effective until at least thirty (30) days after receipt by Lender of
      written notice thereof.

            (j) LIMITATIONS ON DISPOSITION. Grantor will not sell, lease,
      transfer or otherwise dispose of any significant portion of the
      Collateral, without Lender's prior written consent.

            (k) FURTHER IDENTIFICATION OF COLLATERAL. Grantor will, if so
      requested by Lender, furnish to Lender, as often as Lender reasonably
      requests, statements and schedules further identifying and describing the
      Collateral and such other reports in connection with the Collateral as
      Lender may reasonably request, all in reasonable detail.

            (l) NOTICES. Grantor will advise Lender promptly, in reasonable
      detail, (i) of any material lien, security interest, encumbrance or claim
      made or asserted against any of the Collateral, (ii) of any material
      change in the composition of the Collateral, and (iii) of the occurrence
      of any other event which would have a material adverse effect on the
      aggregate value of the Collateral or on the security interests created
      hereunder.

            (m) RIGHT OF INSPECTION. During regular business hours and upon
      reasonable prior notice (unless an Event of Default has occurred and is
      continuing, in which case at all times), Lender shall have full and free
      access to all the books and records and correspondence of Grantor, and
      Lender or its representatives may examine the same, take extracts
      therefrom and make photocopies thereof, and Grantor agrees to render to
      Lender, at Grantor's cost and expense, such clerical and other assistance
      as may be reasonably requested with regard thereto. Lender and its
      representatives shall also have the right to enter into and upon any
      premises where any of the Equipment or Inventory is located for the
      purpose of


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      inspecting the same, observing its use or otherwise protecting its
      interests therein.

            (n) CONTINUOUS PERFECTION. Grantor will not change its name,
      identity or corporate structure in any manner which might make any
      financing or continuation statement filed in connection herewith seriously
      misleading within the meaning of section 9-402(7) of the UCC (or any other
      then applicable provision of the UCC) unless Grantor shall have given
      Lender at least thirty (30) days' prior written notice thereof and shall
      have taken all action (or made arrangements to take such action
      substantially simultaneously with such change if it is impossible to take
      such action in advance) necessary or reasonably requested by Lender to
      amend such financing statement or continuation statement so that it is not
      seriously misleading.

            (o) REAL PROPERTY. In the event Grantor hereafter acquires any real
      property or any interest in real property, Grantor shall notify Lender in
      writing in advance of the acquisition thereof, and if requested by Lender
      shall grant Lender a first priority mortgage lien on such property
      concurrently with the acquisition thereof, and agrees not to grant any
      lien, encumbrance, mortgage or security interest in such real property to
      any other person without Lender's prior written consent. In the event
      Grantor currently owns any real property or any interest in real property,
      Grantor shall promptly notify Lender in writing, and upon Lender's request
      shall grant Lender a first priority mortgage lien on such property.

      6.    LENDER'S APPOINTMENT AS ATTORNEY-IN-FACT.

            (a) Grantor hereby irrevocably constitutes and appoints Lender and
      any officer or agent thereof, with full power of substitution, as its true
      and lawful attorney-in-fact with full irrevocable power and authority in
      the place and stead of Grantor and in the name of Grantor or in its own
      name, from time to time in Lender's discretion, for the purpose of
      carrying out the terms of this Security Agreement, to take any and all
      appropriate action and to execute and deliver any and all documents and
      instruments which may be necessary or desirable to accomplish the purposes
      of this Security Agreement and, without limiting the generality of the
      fore going, hereby gives Lender the power and right, on behalf of Grantor,
      without notice to or assent by Grantor to do the following:

            (i)   to ask, demand, collect, receive and give acquittances and
                  receipts for any and all moneys due and to become due under
                  any Collateral and, in the name of Grantor or its own name or
                  otherwise, to take possession of and endorse and collect any
                  checks, drafts, notes, acceptances or other Instruments for
                  the payment of moneys due under any Collateral and to file any
                  claim or to take any other action or proceeding in any court
                  of law or equity or otherwise deemed appropriate by Lender for
                  the purpose of collecting any and all such moneys due under
                  any Collateral whenever payable and to file any claim or to
                  take any other action or proceeding in any court of law or
                  equity or otherwise deemed appropriate by Lender for the
                  purpose of collecting any and all such moneys due under any
                  Collateral whenever payable;

            (ii)  to pay or discharge taxes, liens, security interests or other
                  encumbrances levied or placed on or threatened against the
                  Collateral, to effect any repairs or any insurance called for
                  by the terms of this Security Agreement and to pay all or any
                  part of the premiums therefor and the costs thereof; and

            (iii) (A) to direct any party liable for any payment under any of
                  the Collateral to make payment of any and all moneys due, and
                  to become


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                  due thereunder, directly to Lender or as Lender shall direct;
                  (B) to receive payment of and receipt for any and all moneys,
                  claims and other amounts due, and to become due at any time,
                  in respect of or arising out of any Collateral; (C) to sign
                  and indorse any invoices, freight or express bills, bills of
                  lading, storage or warehouse receipts, drafts against debtors,
                  assignments, verifications and notices in connection with
                  accounts and other Documents constituting or relating to the
                  Collateral; (D) to commence and prosecute any suits, actions
                  or proceedings at law or in equity in any court of competent
                  jurisdiction to collect the Collateral or any part thereof and
                  to enforce any other right in respect of any Collateral; (E)
                  to defend any suit, action or proceeding brought against
                  Grantor with respect to any Collateral; (F) to settle,
                  compromise or adjust any suit, action or proceeding described
                  above and, in connection therewith, to give such discharges or
                  releases as Lender may deem appropriate; and (G) generally to
                  sell, transfer, pledge, make any agreement with respect to or
                  otherwise deal with any of the Collateral as fully and
                  completely as though Lender were the absolute owner thereof
                  for all purposes, and to do, at Lender's option and Grantor's
                  expense, at any time, or from time to time, all acts and
                  things which Lender reasonably deems necessary to protect,
                  preserve or realize upon the Collateral and Lender's lien
                  therein, in order to effect the intent of this Security
                  Agreement, all as fully and effectively as Grantor might do.

            (b) Grantor hereby ratifies, to the extent permitted by law, all
      that said attorneys shall lawfully do or cause to be done by virtue
      hereof. The power of attorney granted pursuant to this Section 6 is a
      power coupled with an interest and shall be irrevocable until the
      Obligations are indefeasibly paid in full. Lender hereby agrees that it
      shall not exercise the power of attorney granted to it under this Section
      6 unless or until an Event of Default has occurred.

            (c) The powers conferred on Lender hereunder are solely to protect
      Lender's interests in the Collateral and shall not impose any duty upon it
      to exercise any such powers. Lender shall be accountable only for amounts
      that it actually receives as a result of the exercise of such powers and
      neither it nor any of its officers, directors, employees or agents shall
      be responsible to Grantor for any act or failure to act, except for its
      own gross negligence or willful misconduct.

            (d) Grantor also authorizes Lender, at any time and from time to
      time upon the occurrence and during the continuation of any Event of
      Default, (i) to communicate in its own name with any party to any Contract
      with regard to the assignment of the right, title and interest of Grantor
      in and under the Contracts hereunder and other matters relating thereto
      and (ii) to execute, in connection with the sale provided for in Section 8
      hereof, any endorsements, assignments or other instruments of conveyance
      or transfer with respect to the Collateral.

      7. PERFORMANCE BY LENDER OF GRANTORS' OBLIGATION. If Grantor fails to
perform or comply with any of its agreements contained herein (after notice, to
the extent required to be delivered by Lender hereunder) and Lender, as provided
for by the terms of this Security Agreement, shall itself perform or comply, or
otherwise cause performance or compliance, with such agreement, the reasonable
expenses of Lender incurred in connection with such performance or compliance,
together with interest thereon at the rate then in effect in respect of the
Loan, shall be payable by Grantor to Lender on demand and shall constitute
Obligations secured hereby.


                                       9
<PAGE>

      8.    REMEDIES, RIGHTS UPON DEFAULT.

            (a) If an Event of Default shall occur and be continuing, Lender may
      accelerate the Obligations and declare the Obligations to be immediately
      due and payable, without notice or demand, exercise all other rights and
      remedies granted to it in this Security Agreement and in any other
      instrument or agreement securing, evidencing or relating to the
      Obligations, and exercise all rights and remedies of a secured party under
      the UCC. Without limiting the generality of the foregoing, Grantor
      expressly agrees that in any such event Lender, without demand of
      performance or other demand, advertisement or notice of any kind (except
      the notice specified below of time and place of public or private sale) to
      or upon Grantor or any other person (all and each of which demands,
      advertisements and/or notices are hereby expressly waived to the maximum
      extent permitted by the UCC and other applicable law), may forthwith
      collect, receive, appropriate and realize upon the Collateral, or any part
      thereof, and/or may forthwith sell, lease, assign, give an option or
      options to purchase, or sell or otherwise dispose of and deliver said
      Collateral (or contract to do so), or any part thereof, in one or more
      parcels at public or private sale or sales, at any exchange or broker's
      board or at any of Lender's offices or elsewhere at such prices as it may
      deem best, for cash or on credit or for future delivery without assumption
      of any credit risk. Lender shall have the right upon any such public sale
      or sales, and, to the extent permitted by law, upon any such private sale
      or sales, to purchase the whole or any part of said Collateral so sold,
      free of any right or equity of redemption, which equity of redemption
      Grantor hereby releases. Grantor further agrees, at Lender's request, to
      assemble the Collateral and make it available to Lender at places which
      Lender shall reasonably select, whether at Grantor's premises or
      elsewhere. Lender shall apply the net proceeds of any such collection,
      recovery, receipt, appropriation, realization or sale, as provided in
      Section 8(d) hereof, Grantor remaining liable for any deficiency remaining
      unpaid after such application, and only after so paying over such net
      proceeds and after the payment by Lender of any other amount required by
      any provision of law, including section 9-504(1)(c) of the UCC, need
      Lender account for the surplus, if any, to Grantor. To the maximum extent
      permitted by applicable law, Grantor waives all claims, damages, and
      demands against Lender arising out of the repossession, retention or sale
      of the Collateral except such as arise out of the gross negligence or
      wilful misconduct of Lender. Grantor agrees that the Lender need not give
      more than ten (10) days' notice (which notification shall be deemed given
      when mailed or delivered on an overnight basis, postage prepaid, addressed
      to Grantor at its address referred to in Section 12 hereof) of the time
      and place of any public sale or of the time after which a private sale may
      take place and that such notice is reasonable notification of such
      matters. Grantor shall remain liable for any deficiency if the proceeds of
      any sale or disposition of the Collateral are insufficient to pay all
      amounts to which Lender is entitled, Grantor also being liable for the
      fees of any attorneys employed by Lender to collect such deficiency.

            (b) Grantor also agrees to pay all costs of Lender, including,
      without limitation, reasonable attorneys' fees, incurred in connection
      with the enforcement of any of its rights and remedies hereunder.

            (c) Grantor hereby waives presentment, demand, protest or any notice
      (to the maximum extent permitted by applicable law) of any kind in
      connection with this Security Agreement or any Collateral.

            (d) The Proceeds of any sale, disposition or other realization upon
      all or any part of the Collateral shall be distributed by Lender in the
      following order of priorities:

                  FIRST, to Lender in an amount sufficient to pay in full the
            reasonable expenses of


                                       10
<PAGE>

            Lender in connection with such sale, disposition or other
            realization, including all expenses, liabilities and advances
            incurred or made by Lender in connection therewith, including,
            without limitation, reasonable attorney's fees;

                  SECOND, to Lender (or such other holder of the Obligations) in
            an amount equal to the then unpaid Obligations;

                  FINALLY, upon payment in full of all of the Obligations, to
            pay to Grantor, or its representatives or as a court of competent
            jurisdiction may direct, any surplus then remaining from such
            Proceeds.

      9. EVENTS OF DEFAULT. An Event of Default shall be deemed to have occurred
upon the occurrence of any of the following events:

            (a) Grantor shall fail to make any payment when due under the terms
      of the Note or an Event of Default shall occur under the Note;

            (b) Grantor shall fail to perform any obligation or observe any
      covenant arising under this Security Agreement or any other document,
      instrument or agreement executed and delivered in connection with or
      relating to the Obligations and such failure is not cured within fifteen
      (15) business days after notice from Lender, or should any representation
      or warranty made by Grantor prove to be untrue or misleading in any
      material respect when made;

            (c) Any of the assets of Grantor with a value in excess of $50,000
      shall be attached, seized, levied upon or subjected to a writ or distress
      warrant, or come within the possession of any receiver, trustee, custodian
      or assignee for the benefit of creditors of Grantor and shall remain
      unstayed or undismissed for 10 consecutive days; or any person shall apply
      for the appointment of a receiver, trustee or custodian for any of the
      assets of Grantor and shall remain unstayed or undismissed for 10
      consecutive days; or Grantor shall have concealed, removed or permitted to
      be concealed or removed, any part of its property with intent to hinder,
      delay or defraud its creditors or any of them or made or suffered a
      transfer of any of its property or the incurring of an obligation which
      may be fraudulent under any bankruptcy, fraudulent conveyance or other
      similar law;

            (d) A case or proceeding shall have been commenced against Grantor
      in a court having competent jurisdiction seeking a decree or order in
      respect of Grantor (i) under the Bankruptcy Code, or any other applicable
      Federal, state or foreign bankruptcy or other similar law, (ii) appointing
      a custodian, receiver, liquidator, assignee, trustee or sequestrator (or
      similar official) of Grantor or of any substantial part of its properties,
      or (iii) ordering the winding-up or liquidation of the affairs of Grantor
      and such case or proceeding shall remain undismissed or unstayed for 30
      consecutive days or such court shall enter a decree or order granting the
      relief sought in such case or proceeding;

            (e) Grantor shall (i) file a petition seeking relief under the
      Bankruptcy Code, or any other applicable Federal, State or foreign
      bankruptcy or other similar law, (ii) consent to the institution of
      proceedings thereunder or to the filing of any such petition or to the
      appointment of or taking possession by a custodian, receiver, liquidator,
      assignee, trustee or sequestrator (or similar official) of Grantor or of
      any substantial part of its properties, (iii) fail generally to pay its
      debts as such debts become due, or (iv) take any corporate action in
      furtherance of any such action; or

            (f) Grantor shall fail to deliver any documents, instruments or
      agreements required by Lender to perfect a security interest, mortgage or
      lien on any of the Collateral or its interests in


                                       11
<PAGE>

      real property within two business days after delivery of such documents,
      instruments or agreements to Grantor.

      10. LIMITATION ON LENDER'S DUTY IN RESPECT OF COLLATERAL. Lender shall use
reasonable care with respect to the Collateral in its possession or under its
control. Lender shall not have any other duty as to any Collateral in its
possession or control or in the possession or control of any agent or nominee of
it or any income thereon or as to the preservation of rights against prior
parties or any other rights pertaining thereto. Upon request of Grantor, Lender
shall account for any moneys received by it in respect of any foreclosure on or
disposition of the Collateral.

      11. REINSTATEMENT. This Agreement shall remain in full force and effect
and continue to be effective should any petition be filed by or against Grantor
for liquidation or reorganization, should Grantor become insolvent or make an
assignment for the benefit of creditors or should a receiver or trustee be
appointed for all or any significant part of Grantor's assets, and shall
continue to be effective or be reinstated, as the case may be, if at any time
payment and performance of the Obligations, or any part thereof, is, pursuant to
applicable law, rescinded or reduced in amount, or must otherwise be restored or
returned by any obligee of the Obligations, whether as a "voidable preference",
"fraudulent conveyance", or otherwise, all as though such payment or performance
had not been made. In the event that any payment, or any part thereof, is
rescinded, reduced, restored or returned, the Obligations shall be reinstated
and deemed reduced only by such amount paid and not so rescinded, reduced,
restored or returned.

      12. NOTICES. Except as otherwise provided herein, whenever it is provided
herein that any notice, demand, request, consent, approval, declaration or other
communication shall or may be given to or served upon any of the parties by any
other party, or whenever any of the parties desires to give or serve upon any
other communication with respect to this Security Agreement, each such notice,
demand, request, consent, approval, declaration or other communication shall be
in writing and shall be delivered in person with receipt acknowledged, or sent
via overnight courier, addressed as hereafter set forth, or mailed by registered
or certified mail, return receipt requested, postage prepaid, addressed as
follows:

      If to Grantor:    Prime Outdoor Group, LLC
                        1225 Seventeenth Street
                        Suite 1523
                        Denver, Colorado
                        Attn:  Gina Crist

                        The Prime Group, Inc.
                        77 West Wacker Drive
                        Suite 4200
                        Chicago, Illinois 60601
                        Attn:  Robert J. Rudnik

      If to Lender:     Horizon Group Properties, Inc.
                        77 West Wacker Drive
                        Suite 4200
                        Chicago, Illinois 60601
                        Attn:  Gary Skoien

      13. SEVERABILITY. Any provision of this Security Agreement which is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such


                                       12
<PAGE>

provision in any other jurisdiction.

      14. NO WAIVER; CUMULATIVE REMEDIES. Lender shall not by any act, delay,
omission or otherwise be deemed to have waived any of its rights or remedies
hereunder, and no waiver shall be valid unless in writing, signed by Lender and
then only to the extent therein set forth. A waiver by Lender of any right or
remedy hereunder on any one occasion shall not be construed as a bar to any
right or remedy which Lender would otherwise have had on any future occasion. No
failure to exercise nor any delay in exercising on the part of Lender, any
right, power or privilege hereunder, shall operate as a waiver thereof, nor
shall any single or partial exercise of any right, power or privilege hereunder
preclude any other or future exercise thereof or the exercise of any other
right, power or privilege. The rights and remedies hereunder provided are
cumulative and may be exercised singly or concurrently, and are not exclusive of
any rights and remedies provided by law. None of the terms or provisions of this
Security Agreement may be waived, altered, modified or amended except by an
instrument in writing, duly executed by Lender and, where applicable by Grantor.

      15.   SUCCESSOR AND ASSIGNS; GOVERNING LAW.

            (a) This Security Agreement and all obligations of Grantor hereunder
      shall be binding upon the successors and assigns of Grantor, and shall,
      together with the rights and remedies of Lender hereunder, inure to the
      benefit of Lender, and all future holders of instruments or agreements
      evidencing the Obligations and their respective successors and assigns. No
      sales of participations, other sales, assignments, transfers or other
      dispositions of any agreement governing or instrument evidencing the
      Obligations or any portion thereof or interest therein shall in any manner
      affect the security interest granted to Lender hereunder.

            (b) This Security Agreement shall be governed by, and be construed
      and interpreted in accordance with, the laws of the State of Illinois.

      16. FURTHER INDEMNIFICATION. Grantor agrees to pay, and to save Lender
harmless from, any and all liabilities with respect to, or resulting from any
delay in paying, any and all excise, sales or other similar taxes which may be
payable or determined to be payable with respect to any of the Collateral or in
connection with any of the transactions contemplated by this Security Agreement.

      17. WAIVER OF JURY TRIAL AND WAIVER. GRANTOR WAIVES ALL RIGHT TO TRIAL BY
JURY IN ANY ACTION OR PROCEEDING TO ENFORCE OR DEFEND ANY RIGHTS OR REMEDIES
HEREUNDER, UNDER THE NOTE OR UNDER ANY OTHER DOCUMENT, INSTRUMENT OR AGREEMENT
RELATED TO THE OBLIGATIONS. AS PART OF THE CONSIDERATION FOR VALUE THIS DAY
RECEIVED, GRANTOR HEREBY CONSENTS TO THE JURISDICTION OF ANY STATE OR FEDERAL
COURT LOCATED WITHIN THE COUNTY OF COOK, STATE OF ILLINOIS, AND WAIVES PERSONAL
SERVICE OF ANY AND ALL PROCESS UPON GRANTOR, AND CONSENTS THAT ALL SUCH SERVICE
OF PROCESS BY MADE BY REGISTERED MAIL DIRECTED TO GRANTOR AT THE ADDRESSES
PROVIDED IN SECTION 12 ABOVE AND SERVICE SO MADE SHALL BE DEEMED TO BE COMPLETED
FIVE (5) BUSINESS DAYS AFTER THE SAME SHALL HAVE BEEN DEPOSITED IN THE UNITED
STATES MAILS, POSTAGE PREPAID. GRANTOR WAIVES ANY OBJECTION TO VENUE OF ANY
ACTION INSTITUTED HEREUNDER AND CONSENTS TO THE GRANTING OF SUCH LEGAL OR
EQUITABLE RELIEF AS IS DEEMED APPROPRIATE BY THE COURT.

                              [INTENTIONALLY BLANK]


                                       13
<PAGE>

      IN WITNESS WHEREOF, each of the parties hereto has caused this Security
Agreement to be executed and delivered by its duly authorized officer on the
date first set forth above.

                                          PRIME OUTDOOR GROUP, LLC

                                           By:  /s/ Mark T. Harris
                                               -----------------------
                                           Name:    Mark T. Harris
                                                 ---------------------
                                           Title:   President
                                                  --------------------

Accepted and acknowledged by:

HORIZON GROUP PROPERTIES, L.P.

By:  Horizon Group Properties, Inc., general partner

By:  /s/ David R. Tinkham
    ------------------------------------------------
Name:    David R. Tinkham
      ----------------------------------------------
Title:   CFO
       ---------------------------------------------


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