Exhibit 99.B(d)(9)

INVESTMENT SUB-ADVISORY AGREEMENT
SEI INSTITUTIONAL INVESTMENTS TRUST

AGREEMENT made as of November 13, 2019, between SEI Investments Management Corporation (the "Adviser") and AllianceBernstein L.P. (the "Sub-Adviser").

WHEREAS, SEI Institutional Investments Trust, a Massachusetts business trust (the "Trust"), is registered as an open-end management investment company under the Investment Company Act of 1940, as amended (the "1940 Act"); and

WHEREAS, the Adviser has entered into an Investment Advisory Agreement dated June 14, 1996, as amended (the "Advisory Agreement"), with the Trust, pursuant to which the Adviser acts as investment adviser to the series of the Trust set forth on Schedule A attached hereto (the "Fund"), as such Schedule may be amended by mutual agreement of the parties hereto; and

WHEREAS, the Adviser, with the approval of the Trust, desires to retain the Sub-Adviser to provide investment advisory services to the Adviser in connection with the management of the Fund, and the Sub-Adviser is willing to render such investment advisory services.

NOW, THEREFORE, the parties hereto agree as follows:

1. Duties of the Sub-Adviser. Subject to supervision by the Adviser and the Trust's Board of Trustees, the Sub-Adviser shall manage all of the securities and other assets of the Fund entrusted to it hereunder (the "Assets"), including the purchase, retention and disposition of the Assets, in accordance with the Fund's investment objectives, policies and restrictions as stated in the Fund's prospectus and statement of additional information, as currently in effect and as amended or supplemented from time to time (referred to collectively as the "Prospectus"), and subject to the following:

(a) The Sub-Adviser shall provide supervision of the Fund's investments and, in consultation with and subject to the direction of the Adviser, determine from time to time what Assets will be purchased, retained or sold by the Fund, and what portion of the Assets will be invested or held uninvested in cash.

(b) In the performance of its duties and obligations under this Agreement, the Sub-Adviser shall act in conformity with the Trust's Declaration of Trust (as defined herein) and the Prospectus and with the instructions and directions of the Adviser and of the Board of Trustees of the Trust and will conform to and comply with the requirements of the 1940 Act, the Internal Revenue Code of 1986 (the "Code"), and all other applicable federal and state laws and regulations, as each is amended from time to time. The Adviser agrees promptly to deliver any amendment or supplement to the Prospectus to the Sub-Adviser on an on-going basis, and until the Adviser delivers any such amendment or supplement to the Sub-Adviser, the Sub-Adviser shall be fully protected in relying on the Prospectus as previously furnished.

(c) The Sub-Adviser shall determine the Assets to be purchased or sold by the Fund and will place orders with or through such persons, brokers or dealers to carry out the policy with respect to brokerage set forth in the Fund's Registration Statement and Prospectus or as the Board of Trustees or the Adviser may direct from time to time, in conformity with federal securities laws. In executing Fund transactions and selecting brokers or dealers, the Sub-Adviser will use its best efforts to seek on behalf of the Fund the best overall terms available. In assessing the best overall terms available for any transaction, the Sub-Adviser shall consider all factors that it deems relevant, including the breadth of the market in the security, the price of the security, the financial condition and execution capability of the broker or dealer, and the reasonableness of the commission, if any, both for the specific transaction and on a continuing basis. In evaluating the best overall terms available, and in selecting the broker-dealer to execute a particular transaction, the Sub-Adviser may also consider the brokerage and research services (as those terms are defined in Section 28(e) of the Securities Exchange Act of 1934) provided to the Fund and/or other accounts over which the Sub-Adviser or an affiliate of the Sub-Adviser may exercise investment discretion. The Sub-Adviser is authorized, subject to the prior approval of the Trust's Board of Trustees, to pay to a broker or dealer who provides such brokerage and research services a commission for executing a portfolio transaction for the Fund which is in excess of the amount of commission another broker or dealer would have charged for effecting that transaction if, but only if, the Sub-Adviser determines in good faith that such commission was reasonable in relation to the value of the brokerage and research services provided by such broker or dealer -- viewed in terms of that particular transaction or in terms of the overall responsibilities of the Sub-Adviser to the Fund. In addition, the Sub-Adviser is authorized to allocate purchase and sale orders for Fund securities to brokers or dealers that are affiliated with the Adviser, Sub-Adviser or the Trust's principal underwriter if the Sub-Adviser believes that the quality of the transaction and the commission are comparable to what they would be with other qualified firms. In no instance, however, will the Fund's Assets be purchased from or sold to the Adviser, Sub-Adviser, the Trust's principal underwriter, or any affiliated person of either the Trust, Adviser, the Sub-Adviser or the principal underwriter, acting as principal in the transaction, except to the extent permitted by the Securities and Exchange Commission ("SEC") and the 1940 Act.

(d) The Sub-Adviser shall maintain all books and records with respect to transactions involving the Assets required by subparagraphs (b)(5), (6), (7), (9), (10) and (11) and paragraph (f) of Rule 31a-1 under the 1940 Act and shall render to the Adviser or the Board of Trustees such periodic and special reports as the Adviser or Board of Trustees may reasonably request.

The Sub-Adviser shall keep the books and records required to be maintained by the Sub-Adviser by this Agreement and shall timely furnish to the Adviser all information relating to the Sub-Adviser's services under this Agreement needed by the Adviser to keep the other books and records of the Fund required by Rule 31a-1 under the 1940 Act. The Sub-Adviser shall also furnish to the Adviser any other information that is required to be filed by the Adviser or the Trust with the SEC or sent to shareholders under the 1940 Act (including the rules adopted thereunder) or any exemptive or other relief that the Adviser or the Trust obtains from the SEC. The Sub-Adviser agrees that all records that it maintains on behalf of the Fund are property of the Fund and the Sub-Adviser will surrender promptly to the Fund any of such records upon the Fund's request; provided, however, that the Sub-Adviser may retain a copy of such records. In addition, for the duration of this Agreement, the Sub-Adviser shall preserve for the periods prescribed by Rule 31a-2 under the 1940 Act any such records as are required to be maintained by it pursuant to this Agreement, and shall transfer said records to any successor sub-adviser upon the termination of this Agreement (or, if there is no successor sub-adviser, to the Adviser).

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(e) The Sub-Adviser shall provide the Fund's custodian on each business day with information relating to all transactions concerning the Fund's Assets and shall provide such information and such periodic or special reports as the Adviser or Board of Trustees may reasonably request.

(f) The Adviser understands that the Sub-Adviser now acts, will continue to act and may act in the future as investment manager or adviser to fiduciary and other managed accounts, and as investment manager or adviser to other investment companies, including any offshore entities, or accounts, and the Fund has no objection to the Sub-Adviser's so acting, provided that whenever the Fund and one or more other investment companies or accounts managed or advised by the Sub-Adviser have available funds for investment, investments suitable and appropriate for each will be allocated in accordance with a formula believed to be equitable to each company and account. The Adviser recognizes that in some cases this procedure may adversely affect the size of the position obtainable for the Fund. In addition, the Adviser understands that the persons employed by the Sub-Adviser to assist in the performance of the Sub-Adviser's duties under this Agreement will not devote their full time to such service and nothing contained in this Agreement shall be deemed to limit or restrict the right of the Sub-Adviser or any affiliate of the Sub-Adviser to engage in and devote time and attention to other businesses or to render services of whatever kind in nature.

(g) The Sub-Adviser shall promptly notify the Adviser of any financial condition that is likely to impair the Sub-Adviser's ability to fulfill its commitment under this Agreement.

(h) (i) Except under the circumstances set forth in subsection (ii), the Sub-Adviser shall not be responsible for reviewing proxy solicitation materials or voting and handling proxies in relation to the securities held as Assets in the Fund. The Sub-Adviser shall instruct the custodian and other parties providing services to the Fund to promptly forward misdirected proxies to the Adviser.

(ii) The Sub-Adviser hereby agrees that upon 60 days' written notice from the Adviser, the Sub-Adviser shall assume responsibility for reviewing proxy solicitation materials and voting proxies in relation to the securities held as Assets in the Fund. As of the time as the Sub-Adviser shall assume such responsibilities with respect to proxies under this sub-section (ii), the Adviser shall instruct the custodian and other parties providing services to the Fund to promptly forward misdirected proxies to the Sub-Adviser.

(i) In performance of its duties and obligations under this Agreement, the Sub-Adviser shall not consult with any other sub-adviser to the Fund or a sub-adviser to a portfolio that is under common control with the Fund concerning the Assets, except as permitted by the policies and procedures of the Fund. The Sub-Adviser shall not provide investment advice to any assets of the Fund other than the Assets.

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Services to be furnished by the Sub-Adviser under this Agreement may be furnished through the medium of any of the Sub-Adviser's partners, officers, employees or, to the extent permitted by applicable law, affiliates, and with respect to proxies, a third party proxy voting service.

2. Duties of the Adviser. The Adviser shall continue to have responsibility for all services to be provided to the Fund pursuant to the Advisory Agreement and shall oversee and review the Sub-Adviser's performance of its duties under this Agreement; provided, however, nothing herein shall be construed to relieve the Sub-Adviser of responsibility for compliance with the Fund's investment objectives, policies and restrictions, as provided in Section 1 hereunder.

3. Delivery of Documents. The Adviser has furnished the Sub-Adviser with copies of each of the following documents:

(a) The Trust's Agreement and Declaration of Trust, as filed with the Secretary of State of the Commonwealth of Massachusetts (such Agreement and Declaration of Trust, as in effect on the date of this Agreement and as amended from time to time, herein called the "Declaration of Trust");

(b) By-Laws of the Trust (such By-Laws, as in effect on the date of this Agreement and as amended from time to time, are herein called the "By-Laws");

(c) Prospectus(es) of the Fund; and

(d) The Trust's most recent Registration Statement as filed with the SEC.

4. Compensation to the Sub-Adviser. For the services to be provided by the Sub-Adviser pursuant to this Agreement, the Adviser will pay the Sub-Adviser, and the Sub-Adviser agrees to accept as full compensation therefor, a sub-advisory fee at the rate specified in Schedule B which is attached hereto and made part of this Agreement. The fee will be calculated based on the average daily value of the Assets, excluding cash with respect to a Fund that is an equity fund, under the Sub-Adviser's management and will be paid to the Sub-Adviser monthly. For the avoidance of doubt, notwithstanding the fact that the Agreement has not been terminated, no fee will be accrued under this Paragraph 4 with respect to any day that the value of the Assets under the Sub-Adviser's management equals zero. Except as may otherwise be prohibited by law or regulation (including any then current SEC staff interpretation), the Sub-Adviser may, in its discretion and from time to time, waive a portion of its fee.

5. Limitation of Liability of the Sub-Adviser. The Sub-Adviser shall not be liable for any error of judgment or for any loss suffered by the Adviser in connection with the performance of its obligations under this Agreement, except a loss resulting from: (i) willful misfeasance, bad faith or negligence on the Sub-Adviser's part in the performance of its duties, or (ii) reckless disregard of its obligations and duties under this Agreement, or (iii) a violation of law or any duty imposed by federal or state law.

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6. Reports. During the term of this Agreement, the Adviser agrees to furnish the Sub-Adviser at its principal office all prospectuses, proxy statements, reports to stockholders, sales literature or other materials prepared for distribution to stockholders of the Fund, the Trust or the public that refer to the Sub-Adviser or its clients in any way prior to use thereof and not to use material if the Sub-Adviser reasonably objects in writing within five business days (or such other period as may be mutually agreed) after receipt thereof. The Sub-Adviser's right to object to such materials is limited to the portions of such materials that expressly relate to the Sub-Adviser, its services and its clients. The Adviser agrees to use its reasonable best efforts to ensure that materials prepared by its employees or agents or its affiliates that refer to the Sub-Adviser or its clients in any way are consistent with those materials previously approved by the Sub-Adviser as referenced in the first sentence of this paragraph. Sales literature may be furnished to the Sub-Adviser by first class or overnight mail, facsimile transmission equipment or hand delivery.

7. Change in the Sub-Adviser's Membership. The Sub-Adviser agrees that it shall notify the Adviser of any change in the membership of the general partners of the Sub-Adviser within a reasonable time after such change.

8. Indemnification. The Sub-Adviser shall indemnify and hold harmless the Adviser from and against any and all claims, losses, liabilities or damages (including reasonable attorney's fees and other related expenses) howsoever arising from or in connection with this Agreement or the performance by the Sub-Adviser of its duties hereunder; provided, however, that the Sub-Adviser shall not be required to indemnify or otherwise hold the Adviser harmless under this Paragraph 8 where the claim against, or the loss, liability or damage experienced by the Adviser, is caused by or is otherwise directly related to the Adviser's own willful misfeasance, bad faith or negligence, or to the reckless disregard of its duties under this Agreement.

9. Duration and Termination. This Agreement shall become effective upon its approval by the Trust's Board of Trustees and its execution by the parties hereto. Pursuant to the exemptive relief obtained in the SEC Order dated April 29, 1996, Investment Company Act Release No. 21921, approval of the Agreement by a majority of the outstanding voting securities of the Fund is not required, and the Sub-Adviser acknowledges that it and any other sub-adviser so selected and approved shall be without the protection, if any, accorded by shareholder approval of an investment adviser's receipt of compensation under Section 36(b)of the 1940 Act.

This Agreement shall continue in effect for a period of more than two years from the date hereof only so long as continuance is specifically approved at least annually in conformance with the 1940 Act; provided, however, that this Agreement may be terminated with respect to the Fund: (a) by the Fund at any time, without the payment of any penalty, by the vote of a majority of Trustees of the Trust or by the vote of a majority of the outstanding voting securities of the Fund, (b) by the Adviser at any time, without the payment of any penalty, on not more than 60 days' nor less than 30 days' written notice to the Sub-Adviser, or (c) by the Sub-Adviser at any time, without the payment of any penalty, on 90 days' written notice to the Adviser. This Agreement shall terminate automatically and immediately in the event of its assignment, or in the event of a termination of the Advisory Agreement with the Trust. As used in this Paragraph 9, the terms "assignment" and "vote of a majority of the outstanding voting securities" shall have the respective meanings set forth in the 1940 Act and the rules and regulations thereunder, subject to such exceptions as may be granted by the SEC under the 1940 Act.

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10. Compliance Program of the Sub-Adviser. The Sub-Adviser hereby represents and warrants that:

(a) in accordance with Rule 206(4)-7 under the Investment Advisers Act of 1940, as amended (the "Advisers Act"), the Sub-Adviser has adopted and implemented and will maintain written policies and procedures reasonably designed to prevent violation by the Sub-Adviser and its supervised persons (as such term is defined in the Advisers Act) of the Advisers Act and the rules the SEC has adopted under the Advisers Act; and

(b) to the extent that the Sub-Adviser's activities or services could affect the Fund, the Sub-Adviser has adopted and implemented and will maintain written policies and procedures that are reasonably designed to prevent violation of the "federal securities laws" (as such term is defined in Rule 38a-1 under the 1940 Act) by the Fund and the Sub-Adviser (the policies and procedures referred to in this Paragraph 10(b), along with the policies and procedures referred to in Paragraph 10(a), are referred to herein asthe Sub-Adviser's "Compliance Program").

11. Reporting of Compliance Matters.

(a) The Sub-Adviser shall promptly provide to the Trust's Chief Compliance Officer ("CCO") the following documents:

(i) copies of all SEC examination correspondences, including correspondences regarding books and records examinations and "sweep" examinations, issued during the term of this Agreement, in which the SEC identified any concerns, issues or matters (such correspondences are commonly referred to as "deficiency letters") relating to any aspect of the Sub-Adviser's investment advisory business and the Sub-Adviser's responses thereto;

i) a report of any material violations of the Sub-Adviser's Compliance Program or any "material compliance matters" (as such term is defined in Rule 38a-1 under the 1940 Act) that have occurred with respect to the Sub-Adviser's Compliance Program;

(iii) a report of any material changes to the policies and procedures that compose theSub-Adviser's Compliance Program;

(iv) a copy of the Sub-Adviser's chief compliance officer's report (or similar document(s) which serve the same purpose) regarding his or her annual review of the Sub-Adviser's Compliance Program, as required by Rule 206(4)-7 under the Advisers Act; and

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(v) an annual (or more frequently as the Trust's CCO may reasonably request) representation regarding the Sub-Adviser's compliance with Paragraphs 10 and 11 of this Agreement.

(b) The Sub-Adviser shall also provide the Trust's CCO with:

(i) reasonable access to the testing, analyses, reports and other documentation, or summaries thereof, that the Sub-Adviser's chief compliance officer relies upon to monitor the effectiveness of the implementation of the Sub-Adviser's Compliance Program; and

(ii) reasonable access, during normal business hours, to the Sub-Adviser's facilities for the purpose of conducting pre-arranged on-site compliance related due diligence meetings with personnel ofthe Sub-Adviser.

12. Governing Law. This Agreement shall be governed by the internal laws of the Commonwealth of Massachusetts, without regard to conflict of law principles; provided, however, that nothing herein shall be construed as being inconsistent with the 1940 Act.

13. Severability. Should any part of this Agreement be held invalid by a court decision, statute, rule or otherwise, the remainder of this Agreement shall not be affected thereby. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and their respective successors.

14. Notice. Any notice, advice or report to be given pursuant to this Agreement shall be deemed sufficient if delivered or mailed by registered, certified or overnight mail, postage prepaid addressed by the party giving notice to the other party at the last address furnished by the other party:

To the Adviser at:	SEI Investments Management Corporation
	OneFreedom Valley Drive
	Oaks, PA 19456
	Attention: Legal Department
To the Trust's CCO at:	SEI Investments Management Corporation
	One Freedom Valley Drive
	Oaks, PA 19456
	Attention: Russell Emery
To the Sub-Adviser at:	AllianceBemstein L.P.
	1345 Avenue of the Americas
	New York, NY 10105
	Attention: Corporate Legal

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15. Names. The Trust may use the names "AllianceBernstein L.P.," "AllianceBernstein," or "Alliance" only for so long as this Agreement or any extension, renewal or amendment hereof remains in effect. At such times as this Agreement shall no longer be in effect, the Trust shall cease to use such names or any other name indicating that it is advised by or otherwise connected with the Sub-Adviser.

16. Non-Hire/Non-Solicitation. The parties hereby agree that so long as the Sub-Adviser provides services to the Adviser or the Trust and for a period of one year following the date on which the Sub-Adviser ceases to provide services to the Adviser and the Trust, neither party shall for any reason, directly or indirectly, on its own behalf or on behalf of others, hire any person employed by the other party, whether or not such person is a full-time employee or whether or not any person's employment is pursuant to a written agreement or is at-will, without the express written consent of the other party. The parties further agree that, to the extent that a party breaches the covenant described in this paragraph, the other party shall be entitled to pursue all appropriate remedies in law or equity.

17. Amendment of Agreement. This Agreement may be amended only by written agreement of the Adviser and the Sub-Adviser and only in accordance with the provisions of the 1940 Act and the rules and regulations promulgated thereunder.

18. Entire Agreement. This Agreement embodies the entire agreement and understanding between the parties hereto, and supersedes all prior agreements and understandings relating to this Agreement's subject matter. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but such counterparts shall, together, constitute only one instrument.

In the event the terms of this Agreement are applicable to more than one portfolio of the Trust (for purposes of this Paragraph 18, each a "Fund"), the Adviser is entering into this Agreement with the Sub-Adviser on behalf ofthe respective Funds severally and not jointly, with the express intention that the provisions contained in each numbered paragraph hereof shall be understood as applying separately with respect to each Fund as if contained in separate agreements between the Adviser and Sub-Adviser for each such Fund. In the event that this Agreement is made applicable to any additional Funds by way of a Schedule executed subsequent to the date first indicated above, provisions of such Schedule shall be deemed to be incorporated into this Agreement as it relates to such Fund so that, for example, the execution date for purposes of Paragraph 9 of this Agreement with respect to such Fund shall be the execution date of the relevant Schedule.

19. Miscellaneous.

(a) A copy of the Declaration of Trust is on file with the Secretary of State of the Commonwealth of Massachusetts, and notice is hereby given that the obligations of this instrument are not binding upon any of the Trustees, officers or shareholders of the Fund or the Trust.

(b) Where the effect of a requirement of the 1940 Act or the Advisers Act reflected in any provision of this Agreement is altered by a rule, regulation or order of the SEC, whether of special or general application, such provision shall be deemed to incorporate the effect of such rule, regulation or order.

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

SEI Investments Management Corporation		AllianceBernstein L.P.
By:	/s/ Stephen G. MacRae	By:	/s/ Matthew S. White
Name:	Stephen G. MacRae	Name:	Matthew S. White
Title:	Vice President	Title:	Assistant Secretary

Schedule A

to the

Sub-Advisory Agreement

between

SEI Investments Management Corporation

and

AllianceBernstein L.P.

As of November 13, 2019

SEI INSTITUTIONAL INVESTMENTS TRUST

Multi-Asset Real Return Fund
Emerging Markets Equity Fund

World Equity Ex-US Fund

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Schedule B

to the

Sub-Advisory Agreement

between

SEI Investments Management Corporation

and

AllianceBernstein L.P.

As of November 13, 2019

Pursuant to Paragraph 4, the Adviser shall pay the Sub-Adviser compensation at an annual rate as follows:

SEI Institutional Investments Trust
Multi-Asset Real Return Fund	[REDACTED]
Emerging Markets Equity Fund	[REDACTED]
World Equity Ex-US Fund	[REDACTED]

Agreed and Accepted:

SEI Investments Management Corporation		AllianceBernstein L.P.
By:	/s/ Stephen G. MacRae	By:	/s/ Matthew S. White
Name:	Stephen G. MacRae	Name:	Matthew S. White
Title:	Vice President	Title:	Assistant Secretary