# EDGAR Filing Document

**Accession Number:** 0001107414
**File Stem:** 0001410368-25-013982
**Filing Date:** 2025-10
**Character Count:** 13473
**Document Hash:** c2f5a9d3c0e8f8d9ce914159bf3eb5b8
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-25-013982.hdr.sgml**: 20251007

**ACCESSION NUMBER**: 0001410368-25-013982

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250930

**FILED AS OF DATE**: 20251007

**DATE AS OF CHANGE**: 20251007

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** STATE STREET INSTITUTIONAL INVESTMENT TRUST
- **CENTRAL INDEX KEY:** 0001107414

**ORGANIZATION NAME:**
- **EIN:** 046910804
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** N-MFP3
- **SEC ACT:** 1940 Act
- **SEC FILE NUMBER:** 811-09819
- **FILM NUMBER:** 251378648

**BUSINESS ADDRESS:**
- **STREET 1:** ONE CONGRESS STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02114
- **BUSINESS PHONE:** 6176643920

**MAIL ADDRESS:**
- **STREET 1:** ONE CONGRESS STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02114

## Series and Classes Contracts Data

### State Street Treasury Obligations Money Market Fund (Series ID: S000058519)

| Class ID   | Class Name                                          | Ticker Symbol   |
|:---|:---|:---|
| C000192374 | State Street Treasury Obligations Money Market Fund | TAQXX           |

# Form N-MFP3: Monthly Schedule of Portfolio Holdings

## N-MFP: Filer Information
**Submission Type:** N-MFP3
**CIK:** 0001107414

### General Information

**Report for (YYYY-MM-DD):** 2025-09-30

**Registrant Full Name:** STATE STREET INSTITUTIONAL INVESTMENT TRUST

**CIK Number of Registrant:** 0001107414

**LEI of Registrant:** 549300P1E098W6ES7M39

**Name of Series:** State Street Treasury Obligations Money Market Fund

**LEI of Series:** 549300Q6TZ3O71NFFG47

**EDGAR Series Identifier:** S000058519

**Total number of share classes in the series:** 1

**Is this the fund's final filing on Form N-MFP?:** No

**Has the fund acquired or merged with another fund?:** No

## Part A: Series-Level Information about the Fund

### Service Providers
| Role                          | Details                                         | File/CIK Number   |
|:---|:---|:---|
| Investment Adviser            | SSGA Funds Management, Inc.                     | 801-60103         |
| Independent Public Accountant | Ernst & Young  LLP<br>City: Boston<br>State: MA |  |
| Administrator                 | SSGA Funds Management, Inc.                     |  |
| Transfer Agent                | SS&C GIDS, Inc.<br>CIK: 0000027048              | 084-00448         |

### Fund Characteristics & Assets

- **Securities Act File Number:** 333-30810

- **Is this a Feeder Fund?:** Yes

- **Is this a Master Fund?:** No

- **Is this series for insurance company separate accounts?:** No

- **Money Market Fund Category:** Government

- **Is this a Retail Money Market Fund?:** No

- **Is this a Government Money Market Fund?:** No

- **WAM:** 1 days

- **WAL:** 1 days

- **Total Value of Portfolio Securities:** $5505800416.00

- **Amortized Cost of Portfolio Securities:** $5505800416.00

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $15111799.25

- **Net Assets of Series:** $5490688616.75

- **Number of Shares Outstanding (Series):** 5490761774.7600

- **Does the fund seek to maintain a stable price per share?:** Yes

- **Stable Price Per Share:** $1.00

- **Is cash management vehicle an affiliated fund?:** No

- **Does the fund apply liquidity fees?:** No

### Daily & Weekly Liquid Assets
| Date       | Daily Liquid Assets ($)   | Weekly Liquid Assets ($)   | Daily Liquid Assets (%)   | Weekly Liquid Assets (%)   |
|:---|:---|:---|:---|:---|
| 2025-09-02 | $57072747348.11           | $57192747348.11            | 98.1400%                  | 98.3400%                   |
| 2025-09-03 | $57057857783.22           | $57057857783.22            | 97.3000%                  | 97.3000%                   |
| 2025-09-04 | $57509140839.82           | $57509140839.82            | 97.3200%                  | 97.3200%                   |
| 2025-09-05 | $58441677919.65           | $58641677919.65            | 97.3500%                  | 97.6800%                   |
| 2025-09-08 | $58365736135.20           | $58565736135.20            | 97.3400%                  | 97.6800%                   |
| 2025-09-09 | $57056476010.67           | $57256476010.67            | 97.2800%                  | 97.6200%                   |
| 2025-09-10 | $58204763618.18           | $58684763618.18            | 96.8800%                  | 97.6800%                   |
| 2025-09-11 | $55636798742.63           | $55916798742.63            | 97.0800%                  | 97.5700%                   |
| 2025-09-12 | $55321400343.11           | $55601400343.11            | 96.8800%                  | 97.3700%                   |
| 2025-09-15 | $55600603381.18           | $55880603381.18            | 96.9000%                  | 97.3900%                   |
| 2025-09-16 | $55597522535.63           | $55597522535.63            | 97.3800%                  | 97.3800%                   |
| 2025-09-17 | $55812387335.02           | $55812387335.02            | 97.3800%                  | 97.3800%                   |
| 2025-09-18 | $55937924792.42           | $55937924792.42            | 97.3900%                  | 97.3900%                   |
| 2025-09-19 | $55662995738.11           | $55662995738.11            | 97.3600%                  | 97.3600%                   |
| 2025-09-22 | $57435924198.02           | $57435924198.02            | 97.4400%                  | 97.4400%                   |
| 2025-09-23 | $57333518804.56           | $57333518804.56            | 97.4400%                  | 97.4400%                   |
| 2025-09-24 | $57463169712.32           | $57463169712.32            | 97.4400%                  | 97.4400%                   |
| 2025-09-25 | $57999997932.28           | $57999997932.28            | 97.4600%                  | 97.4600%                   |
| 2025-09-26 | $59639805748.49           | $59759805748.49            | 97.5200%                  | 97.7100%                   |
| 2025-09-29 | $59345813839.81           | $59345813839.81            | 97.3300%                  | 97.3300%                   |
| 2025-09-30 | $58436299722.11           | $58436299722.11            | 97.3100%                  | 97.3100%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-09-02 | 4.3200%             |
| 2025-09-03 | 4.3200%             |
| 2025-09-04 | 4.3100%             |
| 2025-09-05 | 4.3100%             |
| 2025-09-08 | 4.3100%             |
| 2025-09-09 | 4.3100%             |
| 2025-09-10 | 4.3100%             |
| 2025-09-11 | 4.3000%             |
| 2025-09-12 | 4.2900%             |
| 2025-09-15 | 4.2800%             |
| 2025-09-16 | 4.2800%             |
| 2025-09-17 | 4.2800%             |
| 2025-09-18 | 4.2600%             |
| 2025-09-19 | 4.2200%             |
| 2025-09-22 | 4.2000%             |
| 2025-09-23 | 4.1900%             |
| 2025-09-24 | 4.1800%             |
| 2025-09-25 | 4.1800%             |
| 2025-09-26 | 4.1700%             |
| 2025-09-29 | 4.1700%             |
| 2025-09-30 | 4.1700%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-09-02 | 1.0002                      |
|  |  |
| 2025-09-03 | 1.0002                      |
|  |  |
| 2025-09-04 | 1.0002                      |
|  |  |
| 2025-09-05 | 1.0003                      |
|  |  |
| 2025-09-08 | 1.0002                      |
|  |  |
| 2025-09-09 | 1.0002                      |
|  |  |
| 2025-09-10 | 1.0002                      |
|  |  |
| 2025-09-11 | 1.0002                      |
|  |  |
| 2025-09-12 | 1.0002                      |
|  |  |
| 2025-09-15 | 1.0002                      |
|  |  |
| 2025-09-16 | 1.0002                      |
|  |  |
| 2025-09-17 | 1.0002                      |
|  |  |
| 2025-09-18 | 1.0002                      |
|  |  |
| 2025-09-19 | 1.0002                      |
|  |  |
| 2025-09-22 | 1.0002                      |
|  |  |
| 2025-09-23 | 1.0002                      |
|  |  |
| 2025-09-24 | 1.0002                      |
|  |  |
| 2025-09-25 | 1.0001                      |
|  |  |
| 2025-09-26 | 1.0002                      |
|  |  |
| 2025-09-29 | 1.0001                      |
|  |  |
| 2025-09-30 | 1.0002                      |
|  |  |

## Part B: Class-Level Information about the Fund

### Class: A

- **Minimum Initial Investment:** $1000000000.00

- **Net Assets of Class:** $5490688616.75

- **Number of Shares Outstanding:** 5490761774.7600

- **Expense Reimbursement/Waiver:** 104305.64

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-09-02 | 1.0002          |
|  |  |
| 2025-09-03 | 1.0002          |
|  |  |
| 2025-09-04 | 1.0002          |
|  |  |
| 2025-09-05 | 1.0003          |
|  |  |
| 2025-09-08 | 1.0002          |
|  |  |
| 2025-09-09 | 1.0002          |
|  |  |
| 2025-09-10 | 1.0002          |
|  |  |
| 2025-09-11 | 1.0002          |
|  |  |
| 2025-09-12 | 1.0002          |
|  |  |
| 2025-09-15 | 1.0002          |
|  |  |
| 2025-09-16 | 1.0002          |
|  |  |
| 2025-09-17 | 1.0002          |
|  |  |
| 2025-09-18 | 1.0002          |
|  |  |
| 2025-09-19 | 1.0002          |
|  |  |
| 2025-09-22 | 1.0002          |
|  |  |
| 2025-09-23 | 1.0002          |
|  |  |
| 2025-09-24 | 1.0002          |
|  |  |
| 2025-09-25 | 1.0001          |
|  |  |
| 2025-09-26 | 1.0002          |
|  |  |
| 2025-09-29 | 1.0001          |
|  |  |
| 2025-09-30 | 1.0002          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-09-02 | $50428964.69              | $35609177.94            |
| 2025-09-03 | $295949753.69             | $864935107.00           |
| 2025-09-04 | $4.83                     | $50474261.00            |
| 2025-09-05 | $0.00                     | $0.00                   |
| 2025-09-08 | $0.00                     | $0.00                   |
| 2025-09-09 | $0.00                     | $0.00                   |
| 2025-09-10 | $0.00                     | $0.00                   |
| 2025-09-11 | $6335307.00               | $441544668.00           |
| 2025-09-12 | $0.00                     | $23060122.00            |
| 2025-09-15 | $0.00                     | $0.00                   |
| 2025-09-16 | $0.00                     | $6376265.00             |
| 2025-09-17 | $0.00                     | $917.30                 |
| 2025-09-18 | $2.00                     | $0.00                   |
| 2025-09-19 | $0.00                     | $61809363.00            |
| 2025-09-22 | $0.00                     | $26000000.00            |
| 2025-09-23 | $239204206.00             | $37287893.00            |
| 2025-09-24 | $366000000.00             | $716741.00              |
| 2025-09-25 | $1707717127.00            | $295561490.00           |
| 2025-09-26 | $366000000.00             | $13207031.00            |
| 2025-09-29 | $432093843.00             | $925411548.00           |
| 2025-09-30 | $0.00                     | $0.00                   |

**Total Gross Subscriptions (Month):** $3463729208.21

**Total Gross Redemptions (Month):** $2781994584.24

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-09-02 | 4.2400%           |
| 2025-09-03 | 4.2400%           |
| 2025-09-04 | 4.2300%           |
| 2025-09-05 | 4.2300%           |
| 2025-09-08 | 4.2300%           |
| 2025-09-09 | 4.2300%           |
| 2025-09-10 | 4.2300%           |
| 2025-09-11 | 4.2200%           |
| 2025-09-12 | 4.2100%           |
| 2025-09-15 | 4.2000%           |
| 2025-09-16 | 4.2000%           |
| 2025-09-17 | 4.2000%           |
| 2025-09-18 | 4.1800%           |
| 2025-09-19 | 4.1400%           |
| 2025-09-22 | 4.1200%           |
| 2025-09-23 | 4.1100%           |
| 2025-09-24 | 4.1000%           |
| 2025-09-25 | 4.1000%           |
| 2025-09-26 | 4.0900%           |
| 2025-09-29 | 4.0900%           |
| 2025-09-30 | 4.0900%           |

**Beneficial/Record Owner Categories**
| Category                  | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Non-financial corporation |  | 99.9900%         | 0.0000%              |

## Part C: Schedule of Portfolio Securities

### Security 1: State Street Treasury Plus Money Market Portfolio

- **C.1 - Title:** State Street Treasury Plus Money Market Portfolio
- **C.6 - Investment Category:** Investment Company
- **Identifiers:** C.3 - CUSIP: FSSgAK183, C.3 - LEI: N/A, C.5 - Other ID: FSSgAK183
- **C.18 - Value (incl. sponsor support):** $5505800416.00
- **C.18.a - Value (excl. sponsor support):** $5505800416.00
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-10-01
- **C.12 - Maturity Date (WAL):** 2025-10-01
- **C.13 - Final Legal Maturity Date:** 2025-10-01
- **Characteristics:** C.9 Eligible Security? Yes, C.14 Has Demand Feature? No, C.15 Has Guarantee? No, C.16 Has Enhancement? No, C.22 Is an Illiquid Security? No, C.20 Is a Daily Liquid Asset? Yes, C.21 Is a Weekly Liquid Asset? Yes, C.23 Categorized at Level 3? No

## N-MFP: Signatures

**Registrant:** STATE STREET INSTITUTIONAL INVESTMENT TRUST

**Date:** 2025-10-07

**By:** /s/ Chad Hallett

**Name of Signing Officer:** Chad Hallett

**Title of Signing Officer:** Deputy Treasurer