Exhibit 99.4

DESCRIPTION OF THE PARTNERSHIP AGREEMENT OF REXFORD INDUSTRIAL REALTY, L.P.

A summary of the material terms and provisions of the Second Amended and Restated Agreement of Limited Partnership of Rexford Industrial Realty, L.P., which we refer to as the “partnership agreement,” is set forth below. This summary is not complete and is subject to and qualified in its entirety by reference to the applicable provisions of Maryland law and the partnership agreement. For more detail, please refer to the partnership agreement itself, a copy of which is filed with the Securities and Exchange Commission. For purposes of this section, references to “we,” “our,” “us,” “our company” and the “general partner” refer to Rexford Industrial Realty, Inc., in our capacity as the general partner of our operating partnership. See “Where You Can Find More Information.”

General

Substantially all of our assets are held by, and substantially all of our operations are conducted through, our operating partnership, either directly or through its subsidiaries. We are the sole general partner of our operating partnership, and, as of December 31, 2015, 57,291,885 common units of partnership interests in our operating partnership, or common units, were outstanding and we owned 96.5% of the outstanding common units. In connection with the formation transactions completed in connection with our initial public offering, we became the general partner of our operating partnership and the prior investors in our portfolio prior to the formation transactions who elected to receive common units in our formation transactions and concurrent private placement were admitted as limited partners of our operating partnership. Our operating partnership is also authorized to issue a class of units of partnership interest designated as LTIP Units, and a class of units of partnership interest designated as Performance Units, each having the terms described below. The common units are not listed on any exchange nor are they quoted on any national market system.

Provisions in the partnership agreement may delay or make more difficult unsolicited acquisitions of us or changes in our control. These provisions could discourage third parties from making proposals involving an unsolicited acquisition of us or change of our control, although some stockholders might consider such proposals, if made, desirable. These provisions also make it more difficult for third parties to alter the management structure of our operating partnership without the concurrence of our board of directors. These provisions include, among others:

Purpose, Business and Management

Our operating partnership was formed for the purpose of conducting any business, enterprise or activity permitted by or under the Maryland Revised Uniform Limited Partnership Act (the “Act”). Our operating partnership may enter into any partnership, joint venture, business trust arrangement, limited liability company or other similar arrangement and may own interests in any other entity engaged in any business permitted by or under the Act, subject to any consent rights set forth in our partnership agreement.

In general, our board of directors manages the business and affairs of our operating partnership by directing our business and affairs, in our capacity as the sole general partner of our operating partnership. Except as otherwise expressly provided in the partnership agreement and subject to the rights of holders of any class or series of partnership interest, all management powers over the business and affairs of our operating partnership are exclusively vested in us, in our capacity as the sole general partner of our operating partnership. We may not be removed as the general partner of our operating partnership, with or without cause, without our consent, which we may give or withhold in our sole and absolute discretion.

Restrictions on General Partner’s Authority

The partnership agreement prohibits us, in our capacity as general partner, from taking any action that would make it impossible to carry out the ordinary business of our operating partnership or performing any act that would subject a limited partner to liability as a general partner in any jurisdiction or any other liability except as provided under the partnership agreement or under the Act. We generally may not, without the prior consent of the partners of our operating partnership (including us), amend, modify or terminate the partnership agreement, except for certain amendments described below that require the approval of each affected partner. We may not, in our capacity as the general partner of our operating partnership, without the consent of a majority in interest of the limited partners (excluding us and any limited partner 50% or more of whose equity is owned, directly or indirectly, by us):

Without the consent of each affected limited partner or in connection with a transfer of all of our interests in our partnership in connection with a merger, consolidation or other combination of our assets with another entity, a sale of all or substantially all of our assets or a reclassification, recapitalization or change in our outstanding stock permitted without the consent of the limited partners as described in “—Transfers of Partnership Interests—Restrictions on Transfers by the General Partner,” or a permitted termination transaction, we may not enter into any contract, mortgage, loan or other agreement that expressly prohibits or restricts us or our operating partnership from performing our or its specific obligations in connection with a redemption of units or expressly prohibits or restricts a limited partner from exercising its redemption rights in full. In addition to any approval or consent required by any other provision of the partnership agreement, we may not, without the consent of each affected partner, amend the partnership agreement or take any other action that would:

Additional Limited Partners

We may cause our operating partnership to issue additional units in one or more classes or series or other partnership interests and to admit additional limited partners to our operating partnership from time to time, on such terms and conditions and for such capital contributions as we may establish in our sole and absolute discretion, without the approval or consent of any limited partner.

The partnership agreement authorizes our operating partnership to issue common units, LTIP Units and Performance Units, and our operating partnership may issue additional partnership interests in one or more additional classes, or one or more series of any of such classes, with such designations, preferences, conversion and other rights, voting powers, restrictions, limitations as to distributions, qualifications and terms and conditions of redemption (including, without limitation, terms that may be senior or otherwise entitled to preference over existing units) as we may determine, in our sole and absolute discretion, without the approval of any limited partner or any other person. Without limiting the generality of the foregoing, we may specify, as to any such class or series of partnership interest, the allocations of items of partnership income, gain, loss, deduction and credit to each such class or series of partnership interest.

Ability to Engage in Other Businesses; Conflicts of Interest

The partnership agreement provides that we may not conduct any business other than in connection with the ownership, acquisition and disposition of partnership interests, the management of the business and affairs of our operating partnership, our operation as a reporting company with a class (or classes) of securities registered under the Exchange Act, our operations as a REIT, the offering, sale, syndication, private placement or public offering of stock, bonds, securities or other interests, financing or refinancing of any type related to our operating partnership or its assets or activities and such activities as are incidental to those activities discussed above. In general, we must contribute any assets or funds that we acquire to our operating partnership whether as capital contributions, loans or otherwise, as appropriate, in exchange for additional partnership interests. We may, however, in our sole and absolute discretion, from time to time hold or acquire assets in our own name or otherwise other than through our operating partnership so long as we take commercially reasonable measures to ensure that the economic benefits and burdens of such property are otherwise vested in our operating partnership.

Distributions

Our operating partnership will distribute such amounts, at such times, as we may in our sole and absolute discretion determine:

Exculpation and Indemnification of General Partner

The partnership agreement provides that we are not liable to our operating partnership or any partner for any action or omission taken in our capacity as general partner, for the debts or liabilities of our operating partnership or for the obligations of our operating partnership under the partnership agreement, except for liability for our fraud, willful misconduct or gross negligence, pursuant to any express indemnity we may give to our operating partnership or in connection with a redemption as described in “—Redemption Rights of Qualifying Parties.” The partnership agreement also provides that any obligation or liability in our capacity as the general partner of our operating partnership that may arise at any time under the partnership agreement or any other instrument, transaction or undertaking contemplated by the partnership agreement will be satisfied, if at all, out of our assets or the assets of our operating partnership only, and no such obligation or liability will be personally binding upon any of our directors, stockholders, officers, employees or agents.

In addition, the partnership agreement requires our operating partnership to indemnify us, our directors and officers, officers of our operating partnership and any other person designated by us against any and all losses, claims, damages, liabilities (whether joint or several), expenses (including, without limitation, attorneys’ fees and

other legal fees and expenses), judgments, fines, settlements and other amounts arising from any and all claims, demands, actions, suits or proceedings, whether civil, criminal, administrative or investigative, that relate to the operations of our operating partnership, unless (i) an act or omission of the person was material to the matter giving rise to the action and either was committed in bad faith or was the result of active and deliberate dishonesty, (ii) in the case of a criminal proceeding, the person had reasonable cause to believe the act or omission was unlawful or (iii) such person actually received an improper personal benefit in violation or breach of any provision of the partnership agreement. Our operating partnership must also pay or reimburse the reasonable expenses of any such person in advance of a final disposition of the proceeding upon its receipt of a written affirmation of the person’s good faith belief that the standard of conduct necessary for indemnification has been met and a written undertaking by or on behalf of the person to repay any amounts paid or advanced if it is ultimately determined that the person did not meet the standard of conduct for indemnification. Our operating partnership is not required to indemnify or advance funds to any person with respect to any action initiated by the person seeking indemnification without our approval (except for any proceeding brought to enforce such person’s right to indemnification under the partnership agreement) or if the person is found to be liable to our operating partnership on any portion of any claim in the action.

Business Combinations and Dissolution of our Operating Partnership

Subject to the limitations on the transfer of our interest in our operating partnership described in “—Transfers of Partnership Interests—Restrictions on Transfers by the General Partner,” we generally have the exclusive power to cause our operating partnership to merge, reorganize, consolidate, sell all or substantially all of its assets or otherwise combine its assets with another entity. We may also elect to dissolve our operating partnership without the consent of any limited partner. However, in connection with the acquisition of properties from persons to whom our operating partnership issues common units or other partnership interests as part of the purchase price, in order to preserve such persons’ tax deferral, our operating partnership may contractually agree, in general, not to sell or otherwise transfer the properties for a specified period of time, or in some instances, not to sell or otherwise transfer the properties without compensating the sellers of the properties for their loss of the tax deferral.

Redemption Rights of Qualifying Parties

Beginning 14 months after first acquiring such common units, each limited partner and some assignees of limited partners will have the right, subject to the terms and conditions set forth in the partnership agreement, to require our operating partnership to redeem all or a portion of the common units held by such limited partner or assignee in exchange for a cash amount per common unit equal to the value of one share of our common stock, determined in accordance with and subject to adjustment under the partnership agreement. Our operating partnership’s obligation to redeem common units does not arise and is not binding against our operating partnership until the sixth business day after we receive the holder’s notice of redemption or, if earlier, the day we notify the holder seeking redemption that we have declined to acquire some or all of the common units tendered for redemption. If we do not elect to acquire the common units tendered for redemption in exchange for shares of our common stock (as described below), our operating partnership must deliver the cash redemption amount, subject to certain exceptions, on or before the first business day of the month that is at least 60 calendar days after we receive the holder’s notice of redemption. Among other limitations, a limited partner or qualifying assignee may not require our operating partnership to redeem its common units if the exchange of such units for shares of our common stock would cause any person to violate the restrictions on ownership and transfer of our stock.

On or before the close of business on the fifth business day after a holder of common units gives notice of redemption to us, we may, in our sole and absolute discretion but subject to the restrictions on the ownership and transfer of our stock set forth in our charter and described in “Restrictions on Ownership and Transfer,” elect to acquire some or all of the common units tendered for redemption from the tendering party in exchange for shares of our common stock, based on an exchange ratio of one share of common stock for each common unit, subject to adjustment as provided in the partnership agreement. The partnership agreement does not require us to register, qualify or list any shares of common stock issued in exchange for common units with the Securities and Exchange Commission, with any state securities commissioner, department or agency, under the Securities Act or the Exchange Act or with any stock exchange.

Transfers of Partnership Interests

Restrictions on Transfers by Limited Partners

Until the expiration of 14 months after the date on which a limited partner acquires a partnership interest, the limited partner generally may not directly or indirectly transfer all or any portion of such partnership interest without our consent, which we may give or withhold in our sole and absolute discretion, except for certain permitted transfers to certain affiliates, family members and charities, and certain pledges of partnership interests to lending institutions in connection with bona fide loans. After the expiration of 14 months after the date on which a limited partner first acquires a partnership interest, the limited partner will have the right to transfer all or any portion of its partnership interest without our consent to any person that is an “accredited investor,” within meaning set forth in Rule 501 promulgated under the Securities Act, upon ten business days prior notice to us, subject to the satisfaction of conditions specified in the partnership agreement, including minimum transfer requirements and our right of first refusal.

Restrictions on Transfers by the General Partner

Except as described below, any transfer of all or any portion of our interest in our operating partnership, whether by sale, disposition, statutory merger or consolidation, liquidation or otherwise, must be approved by the consent of a majority in interest of the limited partners (excluding us and any limited partner 50% or more of whose equity is owned, directly or indirectly, by us). Subject to the rights of holders of any class or series of partnership interest, we may transfer all (but not less than all) of our general partnership interest without the consent of the limited partners in connection with a permitted termination transaction, which is a merger, consolidation or other combination of our assets with another entity, a sale of all or substantially all of our assets or a reclassification, recapitalization or change in any outstanding shares of our stock or other outstanding equity interests, if:

We may also transfer all (but not less than all) of our interest in our operating partnership to an affiliate of us without the consent of any limited partner, subject to the rights of holders of any class or series of partnership interest.

In addition, any transferee of our interest in our operating partnership must be admitted as a general partner of our operating partnership, assume, by operation of law or express agreement, all of our obligations as general partner under the partnership agreement, accept all of the terms and conditions of the partnership agreement and execute such instruments as may be necessary to effectuate the transferee’s admission as a general partner.

We may not voluntarily withdraw as the general partner of our operating partnership without the consent of a majority in interest of the limited partners (excluding us and any limited partner 50% or more of whose equity is owned, directly or indirectly, by us) other than upon the transfer of our entire interest in our operating partnership and the admission of our successor as a general partner of our operating partnership.

LTIP Units

Our operating partnership is authorized to issue a class of units of partnership interest designated as “LTIP Units.” We may cause our operating partnership to issue LTIP Units to persons who provide services to or for the benefit of our operating partnership, for such consideration or for no consideration as we may determine to be appropriate, and we may admit such persons as limited partners of our operating partnership, without the approval or consent of any limited partner. Further, we may cause our operating partnership to issue LTIP Units in one or more classes or series, with such terms as we may determine, without the approval or consent of any limited partner. LTIP Units may be subject to vesting, forfeiture and restrictions on transfer and receipt of distributions pursuant to the terms of any applicable equity-based plan and the terms of any award agreement relating to the issuance of the LTIP Units.

Conversion Rights

Vested LTIP Units are convertible at the option of each limited partner and some assignees of limited partners (in each case, that hold vested LTIP Units) into common units, upon notice to us and our operating partnership, to the extent that the capital account balance of the LTIP unitholder with respect to all of his or her LTIP Units is at least equal to our capital account balance with respect to an equal number of common units. We may cause our operating partnership to convert vested LTIP Units eligible for conversion into an equal number of common units at any time, upon at least 10 and not more than 60 days’ notice to the holder of the LTIP Units.

If we or our operating partnership is party to a transaction, including a merger, consolidation, sale of all or substantially all of our assets or other business combination, as a result of which common units are exchanged for or converted into the right, or holders of common units are otherwise entitled, to receive cash, securities or other property (or any combination thereof), we must cause our operating partnership to convert any vested LTIP Units then eligible for conversion into common units immediately before the transaction, taking into account any special allocations of income that would be made as a result of the transaction. Our operating partnership must use commercially reasonable efforts to cause each limited partner (other than a party to such a transaction or an affiliate of such a party) holding LTIP Units that will be converted into common units in such a transaction to be afforded the right to receive the same kind and amount of cash, securities and other property (or any combination thereof) for such common units that each holder of common units receives in the transaction.

Transfer

Unless an applicable equity-based plan or the terms of an award agreement specify additional restrictions on transfer of LTIP Units, LTIP Units are transferable to the same extent as common units, as described above in “—Transfers of Partnership Interests.”

Voting Rights

Limited partners holding LTIP Units are entitled to vote together as a class with limited partners holding common units and Performance Units on all matters on which limited partners holding common units are entitled to vote or consent, and may cast one vote for each LTIP Unit so held.

Adjustment of LTIP Units

If our operating partnership takes certain actions, including making a distribution of units on all outstanding common units, combining or subdividing the outstanding common units into a different number of common units or reclassifying the outstanding common units, we must adjust the number of outstanding LTIP Units or subdivide or combine outstanding LTIP Units to maintain a one-for-one conversion ratio and economic equivalence between common units and LTIP Units.

Performance Units

Our operating partnership is authorized to issue a class of units of partnership interest designated as “Performance Units.” We may cause our operating partnership to issue Performance Units to persons who provide services to or for the benefit of our operating partnership, for such consideration or for no consideration as we may determine to be appropriate, and we may admit such persons as limited partners of our operating partnership, without the approval or consent of any limited partner. Further, we may cause our operating partnership to issue Performance Units in one or more classes or series, with such terms as we may determine, without the approval or consent of any limited partner. Performance Units may be subject to vesting, forfeiture and restrictions on transfer and receipt of distributions pursuant to the terms of any applicable equity-based plan and the terms of any award agreement relating to the issuance of the Performance Units.

Conversion Rights

Vested Performance Units are convertible at the option of each limited partner and some assignees of limited partners (in each case, that hold vested Performance Units) into common units, upon notice to us and our operating partnership, to the extent that the capital account balance of the Performance Unit unitholder with respect to all of his or her Performance Units is at least equal to our capital account balance with respect to an equal number of common units. We may cause our operating partnership to convert vested Performance Units eligible for conversion into an equal number of common units at any time, upon at least 10 and not more than 60 days’ notice to the holder of the Performance Units.

If we or our operating partnership is party to a transaction, including a merger, consolidation, sale of all or substantially all of our assets or other business combination, as a result of which common units are exchanged for or converted into the right, or holders of common units are otherwise entitled, to receive cash, securities or other property (or any combination thereof), we must cause our operating partnership to convert any vested Performance Units then eligible for conversion into common units immediately before the transaction, taking into account any special allocations of income that would be made as a result of the transaction. Our operating partnership must use commercially reasonable efforts to cause each limited partner (other than a party to such a transaction or an affiliate of such a party) holding Performance Units that will be converted into common units in such a transaction to be afforded the right to receive the same kind and amount of cash, securities and other property (or any combination thereof) for such common units that each holder of common units receives in the transaction.

Transfer

Unless an applicable equity-based plan or the terms of an award agreement specify additional restrictions on transfer of Performance Units, Performance Units are transferable to the same extent as common units, as described above in “—Transfers of Partnership Interests.”

Voting Rights

Limited partners holding Performance Units are entitled to vote together as a class with limited partners holding common units and LTIP Units on all matters on which limited partners holding common units are entitled to vote or consent, and may cast one vote for each Performance Unit so held.

Adjustment of Performance Units

If our operating partnership takes certain actions, including making a distribution of units on all outstanding common units, combining or subdividing the outstanding common units into a different number of common units or reclassifying the outstanding common units, we must adjust the number of outstanding Performance Units or subdivide or combine outstanding Performance Units to maintain a one-for-one conversion ratio and economic equivalence between common units and Performance Units.