Exhibit 10.5

ADDITIONAL BORROWER JOINDER SUPPLEMENT
THIS ADDITIONAL BORROWER JOINDER SUPPLEMENT (this “Agreement”) is made as of
July 29, 2015, by and among THE RUBICON PROJECT, INC., a Delaware corporation
(the “Company”), RUBICON PROJECT HOPPER, INC., a Delaware corporation
(“Hopper”), RUBICON PROJECT UNLATCH, INC., a Delaware corporation (“Unlatch”),
RUBICON PROJECT TURING, INC., a Delaware corporation (“Turing”), RUBICON PROJECT
EDISON, INC., a Delaware corporation (“Edison”), ADVERTISEMENT AUTOMATION
ACCELERATOR, LLC, a Delaware limited liability company (“AAA”), RUBICON PROJECT
BELL, INC., a Delaware corporation (“Bell”), and RUBICON PROJECT CURIE, INC., a
Delaware corporation (“Curie”, together with Hopper, Unlatch, Turing, Edison,
AAA and Bell, individually and collectively, jointly and severally, the
“Additional Borrower”), and SILICON VALLEY BANK, a California chartered bank
(the “Bank”).
NOW, THEREFORE, for value received the undersigned agree as follows:
1.    Reference is hereby made to the Loan and Security Agreement dated
September 27, 2011 (as amended, modified, restated, substituted, extended and
renewed at any time and from time to time, the “Loan Agreement”) by and between
the Company and the Bank. Capitalized terms not otherwise defined in this
Agreement shall have the meanings given to them in the Loan Agreement.
2.    (a)    The Additional Borrower and the Company hereby acknowledge, confirm
and agree that on and as of the date of this Agreement the Additional Borrower
has become a “Borrower” (as that term is defined in the Loan Agreement), and,
along with the Company, is included in the definition of “Borrower” under the
Loan Agreement and the other Loan Documents for all purposes thereof, and as
such shall be jointly and severally liable, as provided in the Loan Documents,
for all Obligations thereunder (whether incurred or arising prior to, on, or
subsequent to the date hereof) and otherwise bound by all of the terms,
provisions and conditions thereof.
(b)    Without in any way implying any limitation on any of the provisions of
this Agreement, the Loan Agreement, or any of the other Loan Documents, the
Additional Borrower hereby assigns, pledges and grants to the Bank as security
for the Obligations, and agrees that the Bank shall have a perfected and
continuing security interest in, and Lien on, (i) all of the Borrower’s
Collateral, whether now owned or existing or hereafter acquired or arising, and
(ii) all returned, rejected or repossessed goods, the sale or lease of which
shall have given or shall give rise to an account or chattel paper. The
Additional Borrower further agrees that the Bank shall have in respect thereof
all of the rights and remedies of a secured party under the Code as well as
those provided in this Agreement, under each of the other Loan Documents and
under applicable laws.
(c)    Without in any way implying any limitation on any of the provisions of
this Agreement, the Additional Borrower agrees to execute such financing
statements, instruments, and other documents as the Bank may require.
(d)    Without in any way implying any limitation on any of the provisions of
this Agreement, the Additional Borrower hereby represents and warrants that all
of the representations and warranties contained in the Loan Documents are true
and correct on and as of the date hereof

687657.6    

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

as if made on and as of such date, both before and after giving effect to this
Agreement, and that no Event of Default or Default has occurred and is
continuing or exists or would occur or exist after giving effect to this
Agreement.
3.    Each Person included in the term “Borrower” hereby covenants and agrees
with the Bank as follows:
(a)    The Obligations include all present and future indebtedness, duties,
obligations, and liabilities, whether now existing or contemplated or hereafter
arising, of any one or more of the Additional Borrower or the Company.
(b)    Reference in this Agreement to the Loan Agreement and the other Loan
Documents to the “Borrower” or otherwise with respect to any one or more of the
Persons now or hereafter included in the definition of “Borrower” shall mean
each and every such Person and any one or more of such Persons, jointly and
severally, unless the context requires otherwise (by way of example, and not
limitation, if only one such Person is the owner of the real property which is
the subject of a mortgage or if only one such Person files reports with the
Securities and Exchange Commission).
(c)    Each Person included in the term “Borrower” in the discretion of its
respective management is to agree among themselves as to the allocation of the
benefits of Letters of Credit and the proceeds of Credit Extensions, provided,
however, that each such Person be deemed to have represented and warranted to
the Bank at the time of allocation that each benefit and use of proceeds is
permitted under the terms of the Loan Agreement and Loan Documents.
(d)    For administrative convenience, each Person included in the term
“Borrower” hereby irrevocably appoints the Company as the Borrower’s
attorney-in-fact, with power of substitution (with the prior written consent of
the Bank in the exercise of its sole and absolute discretion), in the name of
the Company or in the name of the Borrower or otherwise to take any and all
actions with respect to this Agreement, the other Loan Documents, the
Obligations and/or the Collateral (including, without limitation, the proceeds
thereof) as the Company may so elect from time to time, including, without
limitation, actions to (i) request Credit Extensions, apply for and direct the
benefits of Letters of Credits, and direct the Bank to disburse or credit the
proceeds of any Credit Extensions directly to an account of the Company, any one
or more of such Persons or otherwise, which direction shall evidence the making
of such Credit Extension and shall constitute the acknowledgement by each such
Person of the receipt of the proceeds of such Credit Extension or the benefit of
such Letter of Credit, (ii) enter into, execute, deliver, amend, modify,
restate, substitute, extend and/or renew this Agreement, any Additional Borrower
Joinder Supplement, any other Loan Documents, security agreements, mortgages,
deposit account agreements, instruments, certificates, waivers, letter of credit
applications, releases, documents and agreements from time to time, and (iii)
endorse any check or other item of payment in the name of such Person or in the
name of the Company. The foregoing appointment is coupled with an interest,
cannot be revoked without the prior written consent of the Bank, and may be
exercised from time to time through the Company’s duly authorized officer,
officers or other Person or Persons designated by the Company to act from time
to time on behalf of the Company.

687657.6    
2

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

(e)    Each Person included in the term “Borrower” hereby irrevocably authorizes
the Bank to make Credit Extensions to any one or more of such Person, and hereby
irrevocably authorizes the Bank to issue or cause to be issued Letters of Credit
for the account of any or all of such Persons, pursuant to the provisions of
this Agreement upon the written, oral or telephone request any one or more of
the Persons who is from time to time authorized to do so under the provisions of
the most recent certificate of corporate resolutions and/or incumbency of the
Person included in the term “Borrower” on file with the Bank and also upon the
written, oral or telephone request of any one of the Persons who is from time to
time authorized to do so under the provisions of the most recent certificate of
corporate resolutions and/or incumbency for the Company on file with the Bank.
(f)    The Bank assumes no responsibility or liability for any errors, mistakes,
and/or discrepancies in the oral, telephonic, written or other transmissions of
any instructions, orders, requests and confirmations between the Bank and any
one or more of the Persons included in the term “Borrower” or the Bank in
connection with any Credit Extension, any Letter of Credit or any other
transaction in connection with the provisions of this Agreement.
4.    Without implying any limitation on the joint and several nature of the
Obligations, the Bank agrees that, notwithstanding any other provision of this
Agreement, the Persons included in the term “Borrower,” may create reasonable
inter-company indebtedness between or among the Borrowers with respect to the
allocation of the benefits and proceeds of the Credit Extensions under this
Agreement. The Borrowers agree among themselves, and the Bank consents to that
agreement, that each Borrower shall have rights of contribution from all of the
other Borrowers to the extent such Borrower incurs Obligations in excess of the
proceeds of the Credit Extensions received by, or allocated to purposes for the
direct benefit of, such Borrower. All such indebtedness and rights shall be, and
are hereby agreed by the Borrowers to be, subordinate in priority and payment to
the indefeasible repayment in full in cash of the Obligations, and, unless the
Bank agrees in writing otherwise, shall not be exercised or repaid in whole or
in part until all of the Obligations have been indefeasibly paid in full in
cash. The Borrowers agree that all of such inter-company indebtedness and rights
of contribution are part of the Collateral and secure the Obligations. Each
Borrower hereby waives all rights of counterclaim, recoupment and offset between
or among themselves arising on account of that indebtedness and otherwise. Each
Borrower shall not evidence the inter-company indebtedness or rights of
contribution by note or other instrument, and shall not secure such indebtedness
or rights of contribution with any Lien or security. Notwithstanding anything
contained in this Agreement to the contrary, the amount covered by each Borrower
under the Obligations shall be limited to an aggregate amount (after giving
effect to any collections from, rights to receive contribution from or payments
made by or on behalf of any other Borrower in respect of the Obligations) which,
together with other amounts owing by such Borrowers to the Bank under the
Obligations, is equal to the largest amount that would not be subject to
avoidance under any Insolvency Proceeding or any applicable provisions of any
applicable, comparable state or other laws. As used in this Agreement,
“Insolvency Proceeding” shall mean proceedings by or against any Person under
the United States Bankruptcy Code, or any other bankruptcy or insolvency law,
including assignments for the benefit of creditors, compositions, extensions
generally with its creditors, or proceedings seeking reorganization,
arrangement, or other relief.

687657.6    
3

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

5.    (a)    Each Person included in the term “Borrower” hereby represents and
warrants to the Bank that each of them will derive benefits, directly and
indirectly, from each Letter of Credit and from each Credit Extension, both in
their separate capacity and as a member of the integrated group to which each
such Person belongs and because the successful operation of the integrated group
is dependent upon the continued successful performance of the functions of the
integrated group as a whole, because (i) the terms of the consolidated financing
provided under this Agreement are more favorable than would otherwise be
obtainable by such Persons individually, and (ii) the additional administrative
and other costs and reduced flexibility associated with individual financing
arrangements which would otherwise be required if obtainable would substantially
reduce the value to such Persons of the financing.
(b)    Each Person included in the term “Borrower” hereby represents and
warrants that all of the representations and warranties contained in the Loan
Documents are true and correct on and as of the date hereof as if made on and as
of such date, both before and after giving effect to this Agreement, and that no
Event of Default or Default has occurred and is continuing or exists or would
occur or exist after giving effect to this Agreement.
6.    Guaranty.
(a)    Each Person included in the term “Borrower” hereby unconditionally and
irrevocably, guarantees to the Bank:
(i)    the due and punctual payment in full (and not merely the collectibility)
by the other Persons included in the term “Borrower” of the Obligations,
including unpaid and accrued interest thereon, in each case when due and
payable, all according to the terms of this Agreement and the other Loan
Documents;
(ii)    the due and punctual payment in full (and not merely the collectibility)
by the other Persons included in the term “Borrower” of all other sums and
charges which may at any time be due and payable in accordance with this
Agreement or any of the other Loan Documents;
(iii)    the due and punctual performance by the other Persons included in the
term “Borrower” of all of the other terms, covenants and conditions contained in
the Loan Documents; and
(iv)    all the other Obligations of the other Persons included in the term
“Borrower”.
(b)    The obligations and liabilities of each Person included in the term
“Borrower” as a guarantor under this paragraph 6 shall be absolute and
unconditional and joint and several, irrespective of the genuineness, validity,
priority, regularity or enforceability of this Agreement or any of the Loan
Documents or any other circumstance which might otherwise constitute a legal or
equitable discharge of a surety or guarantor. Each Person included in the term
“Borrower” in its capacity as a guarantor expressly agrees that the Bank may, in
its sole and absolute discretion,

687657.6    
4

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

without notice to or further assent of such Borrower and without in any way
releasing, affecting or in any way impairing the joint and several obligations
and liabilities of such Person as a guarantor hereunder:
(i)    waive compliance with, or any defaults under, or grant any other
indulgences under or with respect to any of the Loan Documents;
(ii)    modify, amend, change or terminate any provisions of any of the Loan
Documents (provided the Bank obtains the consent of the other parties to any
such Loan Document if such consent is required by the terms of the applicable
Loan Documents);
(iii)    grant extensions or renewals of or with respect to the Credit
Extensions or any of the Loan Documents;
(iv)    effect any release, subordination, compromise or settlement in
connection with this Agreement or any of the other Loan Documents;
(v)    agree to the substitution, exchange, release or other disposition of the
Collateral or any part thereof, or any other collateral for the Credit
Extensions or to the subordination of any lien or security interest therein;
(vi)    make Credit Extensions for the purpose of performing any term, provision
or covenant contained in this Agreement or any of the other Loan Documents with
respect to which the Borrower shall then be in default;
(vii)    make future Credit Extensions pursuant to the Loan Agreement or any of
the other Loan Documents;
(viii)    assign, pledge, hypothecate or otherwise transfer the Obligations, any
of the other Loan Documents or any interest therein, all as and to the extent
permitted by the provisions of this Agreement;
(ix)    deal in all respects with the other Persons included in the term
“Borrower” as if this paragraph 6 were not in effect;
(x)    effect any release, compromise or settlement with any of the other
Persons included in the term “Borrower”, whether in their capacity as a Borrower
or as a guarantor under this paragraph 6 or any other guarantor; and
(xi)    provide debtor-in-possession financing or allow use of cash collateral
in proceedings under any Insolvency Proceeding, it being expressly agreed by all
Persons included in the term “Borrower” that any such financing and/or use would
be part of the Obligations.
(c)    The obligations and liabilities of each Person included in the term
“Borrower”, as guarantor under this paragraph 6 shall be primary, direct and
immediate, shall not

687657.6    
5

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

be subject to any counterclaim, recoupment, set off, reduction or defense based
upon any claim that such Person may have against any one or more of the other
Persons included in the term “Borrower” and/or any other guarantor and shall not
be conditional or contingent upon pursuit or enforcement by the Bank of any
remedies it may have against Persons included in the term “Borrower” with
respect to this Agreement, or any of the other Loan Documents, whether pursuant
to the terms thereof or by operation of law. Without limiting the generality of
the foregoing, the Bank shall not be required to make any demand upon any of the
Persons included in the term “Borrower”, or to sell the Collateral or otherwise
pursue, enforce or exhaust its or their remedies against the Persons included in
the term “Borrower” or the Collateral either before, concurrently with or after
pursuing or enforcing its rights and remedies hereunder. Any one or more
successive or concurrent actions or proceedings may be brought against each
Person included in the term “Borrower” under this paragraph 6, either in the
same action, if any, brought against any one or more of the Persons included in
the term “Borrower” or in separate actions or proceedings, as often as the Bank
may deem expedient or advisable. Without limiting the foregoing, it is
specifically understood that any modification, limitation or discharge of any of
the liabilities or obligations of any one or more of the Persons included in the
term “Borrower”, any other guarantor or any obligor under any of the Loan
Documents, arising out of, or by virtue of, any bankruptcy, arrangement,
reorganization or similar proceeding for relief of debtors under federal or
state law initiated by or against any one or more of the Persons included in the
term “Borrower”, in their respective capacities as borrowers and guarantors
under this paragraph 6, or under any of the Loan Documents shall not modify,
limit, lessen, reduce, impair, discharge, or otherwise affect the liability of
each Borrower under this paragraph 6 in any manner whatsoever, and this
paragraph 6 shall remain and continue in full force and effect. It is the intent
and purpose of this paragraph 6 that each Person included in the term “Borrower”
shall and does hereby waive all rights and benefits which might accrue to any
other guarantor by reason of any such proceeding, and the Persons included in
the term “Borrower” agree that they shall be liable for the full amount of the
obligations and liabilities under this paragraph 6 regardless of, and
irrespective to, any modification, limitation or discharge of the liability of
any one or more of the Persons included in the term “Borrower”, any other
guarantor or any obligor under any of the Loan Documents, that may result from
any such proceedings.
(d)    Each Person included in the term “Borrower”, as guarantor under this
paragraph 6, hereby unconditionally, jointly and severally, irrevocably and
expressly waives:
(i)    presentment and demand for payment of the Obligations and protest of
non-payment;
(ii)    notice of acceptance of this paragraph 6 and of presentment, demand and
protest thereof;
(iii)    notice of any default hereunder or under or any of the Loan Documents
and notice of all indulgences;
(iv)    notice of any increase in the amount of any portion of or all of the
indebtedness guaranteed by this paragraph 6;

687657.6    
6

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

(v)    demand for observance, performance or enforcement of any of the terms or
provisions of this paragraph 6 or any of the other Loan Documents;
(vi)    all errors and omissions in connection with the Bank’s administration of
all indebtedness guaranteed by this paragraph 6;
(vii)     any right or claim of right to cause a marshalling of the assets of
any one or more of the other Persons included in the term “Borrower”;
(viii)    any act or omission of the Bank which changes the scope of the risk as
guarantor hereunder; and
(ix)    all other notices and demands otherwise required by law which such
Person may lawfully waive.
(e)    Within ten (10) days following any request of the Bank so to do, each
Person included in the term “Borrower” will furnish the Bank and such other
persons as the Bank may direct with a written certificate, duly acknowledged
stating in detail whether or not any credits, offsets or defenses exist with
respect to this paragraph 6.
7.    This Agreement shall be governed by and construed and enforced in
accordance with the laws of the State of California, without regard to
principles of choice of law.
[Signatures Begin on Next Page]

687657.6    
7

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

WITNESS the due execution hereof as of the day and year first written above.
WITNESS/ATTEST:
 
THE RUBICON PROJECT, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

WITNESS/ATTEST:
 
RUBICON PROJECT HOPPER, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

WITNESS/ATTEST:
 
RUBICON PROJECT UNLATCH, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

WITNESS/ATTEST:
 
RUBICON PROJECT TURING, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

WITNESS/ATTEST:
 
RUBICON PROJECT EDISON, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

687657.6    
[Signature Page to Additional Borrower Joinder Supplement]

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

WITNESS/ATTEST:
 
ADVERTISEMENT AUTOMATION ACCELERATOR, LLC
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Authorized Person

WITNESS/ATTEST:
 
RUBICON PROJECT BELL, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

WITNESS/ATTEST:
 
RUBICON PROJECT BELL, INC.
 
 
 
 
 
 
By:
/s/ Jonathan Feldman
 
 
Name: Jonathan Feldman
 
 
Title: Assistant Secretary

WITNESS/ATTEST:
 
SILICON VALLEY BANK
 
 
 
 
 
 
By:
/s/ Victor Le
 
 
Name: Victor Le
 
 
Title: VP

687657.6    
[Signature Page to Additional Borrower Joinder Supplement]