# EDGAR Filing Document

**Accession Number:** 0001107414
**File Stem:** 0001410368-26-022221
**Filing Date:** 2026-3
**Character Count:** 12756
**Document Hash:** 1bc8781b0ae4a5e498961a8141cd9da9
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-022221.hdr.sgml**: 20260306

**ACCESSION NUMBER**: 0001410368-26-022221

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260228

**FILED AS OF DATE**: 20260306

**DATE AS OF CHANGE**: 20260306

**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:** 26729267

**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):** 2026-02-28

**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:** $3159082969.34

- **Amortized Cost of Portfolio Securities:** $3159082969.34

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $9544997.40

- **Net Assets of Series:** $3149537971.94

- **Number of Shares Outstanding (Series):** 3149612814.4000

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2026-02-02 | $64227998520.58           | $64457998520.58            | 98.1400%                  | 98.4900%                   |
| 2026-02-03 | $64564081154.43           | $64794081154.43            | 98.1400%                  | 98.4900%                   |
| 2026-02-04 | $64480145795.68           | $65045145795.68            | 97.6400%                  | 98.4900%                   |
| 2026-02-05 | $63231327027.26           | $63566327027.26            | 97.9400%                  | 98.4600%                   |
| 2026-02-06 | $62290030578.64           | $62855030578.64            | 97.5400%                  | 98.4200%                   |
| 2026-02-09 | $64007190752.67           | $64347190752.67            | 97.9400%                  | 98.4600%                   |
| 2026-02-10 | $63244204006.99           | $63699204006.99            | 97.7400%                  | 98.4400%                   |
| 2026-02-11 | $64564560364.05           | $65129560364.05            | 97.6200%                  | 98.4800%                   |
| 2026-02-12 | $64862084327.83           | $65197084327.83            | 97.9700%                  | 98.4700%                   |
| 2026-02-13 | $63573279279.35           | $63913279279.35            | 97.9000%                  | 98.4200%                   |
| 2026-02-17 | $64171605966.16           | $64401605966.16            | 98.1000%                  | 98.4500%                   |
| 2026-02-18 | $64356956329.29           | $64696956329.29            | 97.9400%                  | 98.4600%                   |
| 2026-02-19 | $66709859577.53           | $66819859577.53            | 98.3400%                  | 98.5000%                   |
| 2026-02-20 | $64012894751.96           | $64352894751.96            | 97.6700%                  | 98.1900%                   |
| 2026-02-23 | $65679855764.75           | $66299855764.75            | 97.7300%                  | 98.6600%                   |
| 2026-02-24 | $65244851941.22           | $65474851941.22            | 97.8800%                  | 98.2200%                   |
| 2026-02-25 | $66170386610.28           | $66510386610.28            | 97.7500%                  | 98.2500%                   |
| 2026-02-26 | $66919281910.22           | $67029281910.22            | 97.9400%                  | 98.1000%                   |
| 2026-02-27 | $63859427446.84           | $64199427446.84            | 97.4900%                  | 98.0000%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2026-02-02 | 3.7500%             |
| 2026-02-03 | 3.7500%             |
| 2026-02-04 | 3.7500%             |
| 2026-02-05 | 3.7500%             |
| 2026-02-06 | 3.7400%             |
| 2026-02-09 | 3.7400%             |
| 2026-02-10 | 3.7300%             |
| 2026-02-11 | 3.7300%             |
| 2026-02-12 | 3.7300%             |
| 2026-02-13 | 3.7400%             |
| 2026-02-17 | 3.7400%             |
| 2026-02-18 | 3.7500%             |
| 2026-02-19 | 3.7500%             |
| 2026-02-20 | 3.7400%             |
| 2026-02-23 | 3.7400%             |
| 2026-02-24 | 3.7400%             |
| 2026-02-25 | 3.7300%             |
| 2026-02-26 | 3.7300%             |
| 2026-02-27 | 3.7400%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2026-02-02 | 1.0001                      |
|  |  |
| 2026-02-03 | 1.0001                      |
|  |  |
| 2026-02-04 | 1.0001                      |
|  |  |
| 2026-02-05 | 1.0002                      |
|  |  |
| 2026-02-06 | 1.0001                      |
|  |  |
| 2026-02-09 | 1.0001                      |
|  |  |
| 2026-02-10 | 1.0001                      |
|  |  |
| 2026-02-11 | 1.0001                      |
|  |  |
| 2026-02-12 | 1.0001                      |
|  |  |
| 2026-02-13 | 1.0001                      |
|  |  |
| 2026-02-17 | 1.0001                      |
|  |  |
| 2026-02-18 | 1.0001                      |
|  |  |
| 2026-02-19 | 1.0001                      |
|  |  |
| 2026-02-20 | 1.0001                      |
|  |  |
| 2026-02-23 | 1.0001                      |
|  |  |
| 2026-02-24 | 1.0001                      |
|  |  |
| 2026-02-25 | 1.0001                      |
|  |  |
| 2026-02-26 | 1.0001                      |
|  |  |
| 2026-02-27 | 1.0001                      |
|  |  |

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

### Class: A

- **Minimum Initial Investment:** $1000000000.00

- **Net Assets of Class:** $3149537971.94

- **Number of Shares Outstanding:** 3149612814.4000

- **Expense Reimbursement/Waiver:** 79047.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-02-02 | 1.0001          |
|  |  |
| 2026-02-03 | 1.0001          |
|  |  |
| 2026-02-04 | 1.0001          |
|  |  |
| 2026-02-05 | 1.0002          |
|  |  |
| 2026-02-06 | 1.0001          |
|  |  |
| 2026-02-09 | 1.0001          |
|  |  |
| 2026-02-10 | 1.0001          |
|  |  |
| 2026-02-11 | 1.0001          |
|  |  |
| 2026-02-12 | 1.0001          |
|  |  |
| 2026-02-13 | 1.0001          |
|  |  |
| 2026-02-17 | 1.0001          |
|  |  |
| 2026-02-18 | 1.0001          |
|  |  |
| 2026-02-19 | 1.0001          |
|  |  |
| 2026-02-20 | 1.0001          |
|  |  |
| 2026-02-23 | 1.0001          |
|  |  |
| 2026-02-24 | 1.0001          |
|  |  |
| 2026-02-25 | 1.0001          |
|  |  |
| 2026-02-26 | 1.0001          |
|  |  |
| 2026-02-27 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-02-02 | $31862743.22              | $15930055.09            |
| 2026-02-03 | $13.52                    | $2183.22                |
| 2026-02-04 | $0.00                     | $14457789.00            |
| 2026-02-05 | $0.00                     | $236889407.00           |
| 2026-02-06 | $0.00                     | $0.00                   |
| 2026-02-09 | $0.00                     | $17644358.00            |
| 2026-02-10 | $0.00                     | $3000000.00             |
| 2026-02-11 | $0.00                     | $25000000.00            |
| 2026-02-12 | $0.00                     | $0.00                   |
| 2026-02-13 | $0.00                     | $0.00                   |
| 2026-02-17 | $0.00                     | $0.00                   |
| 2026-02-18 | $0.00                     | $1831236.00             |
| 2026-02-19 | $5000000.00               | $0.00                   |
| 2026-02-20 | $0.00                     | $0.00                   |
| 2026-02-23 | $0.00                     | $0.00                   |
| 2026-02-24 | $0.00                     | $1069723.00             |
| 2026-02-25 | $0.00                     | $9615673.00             |
| 2026-02-26 | $0.00                     | $0.00                   |
| 2026-02-27 | $0.00                     | $0.00                   |

**Total Gross Subscriptions (Month):** $36862756.74

**Total Gross Redemptions (Month):** $325440424.31

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-02-02 | 3.6700%           |
| 2026-02-03 | 3.6700%           |
| 2026-02-04 | 3.6700%           |
| 2026-02-05 | 3.6700%           |
| 2026-02-06 | 3.6600%           |
| 2026-02-09 | 3.6500%           |
| 2026-02-10 | 3.6500%           |
| 2026-02-11 | 3.6500%           |
| 2026-02-12 | 3.6500%           |
| 2026-02-13 | 3.6600%           |
| 2026-02-17 | 3.6600%           |
| 2026-02-18 | 3.6700%           |
| 2026-02-19 | 3.6700%           |
| 2026-02-20 | 3.6600%           |
| 2026-02-23 | 3.6600%           |
| 2026-02-24 | 3.6600%           |
| 2026-02-25 | 3.6500%           |
| 2026-02-26 | 3.6500%           |
| 2026-02-27 | 3.6600%           |

**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: 5493008OWE0VKOXO4934, C.5 - Other ID: FSSgAK183
- **C.18 - Value (incl. sponsor support):** $3159082969.34
- **C.18.a - Value (excl. sponsor support):** $3159082969.34
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2026-03-02
- **C.12 - Maturity Date (WAL):** 2026-03-02
- **C.13 - Final Legal Maturity Date:** 2026-03-02
- **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:** 2026-03-06

**By:** /s/ Chad Hallett

**Name of Signing Officer:** Chad Hallett

**Title of Signing Officer:** Deputy Treasurer