# EDGAR Filing Document

**Accession Number:** 0001107414
**File Stem:** 0001410368-25-033483
**Filing Date:** 2025-12
**Character Count:** 12638
**Document Hash:** 9cfe086d1eda8029f1adca0511fa0d7c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-25-033483.hdr.sgml**: 20251205

**ACCESSION NUMBER**: 0001410368-25-033483

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20251130

**FILED AS OF DATE**: 20251205

**DATE AS OF CHANGE**: 20251205

**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:** 251551833

**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 Federal Treasury Plus Money Market Fund (Series ID: S000086382)

| Class ID   | Class Name      | Ticker Symbol   |
|:---|:---|:---|
| C000251885 | Advantage Class | ATPXX           |

# 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):** 2025-11-30

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

**CIK Number of Registrant:** 0001107414

**LEI of Registrant:** 549300P1E098W6ES7M39

**Name of Series:** State Street Federal Treasury Plus Money Market Fund

**LEI of Series:** 984500FCIE7E84F01E90

**EDGAR Series Identifier:** S000086382

**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:** $65220569.09

- **Amortized Cost of Portfolio Securities:** $65220569.09

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $262005.58

- **Net Assets of Series:** $64958563.51

- **Number of Shares Outstanding (Series):** 64958549.0800

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2025-11-03 | $54023038075.34           | $54023038075.34            | 97.3900%                  | 97.3900%                   |
| 2025-11-04 | $58238573603.85           | $58238573603.85            | 97.5700%                  | 97.5700%                   |
| 2025-11-05 | $61708093825.87           | $61708093825.87            | 97.7000%                  | 97.7000%                   |
| 2025-11-06 | $61130804324.76           | $61330804324.76            | 97.6800%                  | 98.0000%                   |
| 2025-11-07 | $60168086500.31           | $60368086500.31            | 97.6300%                  | 97.9500%                   |
| 2025-11-10 | $62858393399.05           | $63058393399.05            | 97.7300%                  | 98.0400%                   |
| 2025-11-11 | $0.00                     | $0.00                      | 0.0000%                   | 0.0000%                    |
| 2025-11-12 | $60823928870.88           | $61023928870.88            | 97.6500%                  | 97.9700%                   |
| 2025-11-13 | $59998326745.66           | $59998326745.66            | 97.9400%                  | 97.9400%                   |
| 2025-11-14 | $60923770945.45           | $61173770945.45            | 97.9600%                  | 98.3600%                   |
| 2025-11-17 | $61409937876.36           | $61779937876.36            | 97.6300%                  | 98.2200%                   |
| 2025-11-18 | $62481664756.15           | $62731664756.15            | 97.6700%                  | 98.0600%                   |
| 2025-11-19 | $61666701321.86           | $62166701321.86            | 97.6400%                  | 98.4300%                   |
| 2025-11-20 | $61171123335.90           | $61421123335.90            | 98.0100%                  | 98.4100%                   |
| 2025-11-21 | $61351561095.29           | $61601561095.29            | 98.0100%                  | 98.4100%                   |
| 2025-11-24 | $63322028253.21           | $63572028253.21            | 98.0700%                  | 98.4600%                   |
| 2025-11-25 | $63595511219.16           | $63595511219.16            | 98.4600%                  | 98.4600%                   |
| 2025-11-26 | $64609283659.40           | $64609283659.40            | 98.4800%                  | 98.4800%                   |
| 2025-11-28 | $63064210672.55           | $63064210672.55            | 98.4300%                  | 98.4300%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-11-03 | 4.0900%             |
| 2025-11-04 | 4.0800%             |
| 2025-11-05 | 4.0600%             |
| 2025-11-06 | 4.0600%             |
| 2025-11-07 | 4.0300%             |
| 2025-11-10 | 4.0200%             |
| 2025-11-11 | 0.0000%             |
| 2025-11-12 | 4.0300%             |
| 2025-11-13 | 4.0300%             |
| 2025-11-14 | 4.0300%             |
| 2025-11-17 | 4.0300%             |
| 2025-11-18 | 4.0300%             |
| 2025-11-19 | 4.0200%             |
| 2025-11-20 | 4.0200%             |
| 2025-11-21 | 4.0100%             |
| 2025-11-24 | 4.0100%             |
| 2025-11-25 | 4.0100%             |
| 2025-11-26 | 4.0200%             |
| 2025-11-28 | 4.0400%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-11-03 | 1.0001                      |
|  |  |
| 2025-11-04 | 1.0001                      |
|  |  |
| 2025-11-05 | 1.0001                      |
|  |  |
| 2025-11-06 | 1.0002                      |
|  |  |
| 2025-11-07 | 1.0001                      |
|  |  |
| 2025-11-10 | 1.0001                      |
|  |  |
| 2025-11-11 | 0.0000                      |
|  |  |
| 2025-11-12 | 1.0001                      |
|  |  |
| 2025-11-13 | 1.0001                      |
|  |  |
| 2025-11-14 | 1.0001                      |
|  |  |
| 2025-11-17 | 1.0001                      |
|  |  |
| 2025-11-18 | 1.0001                      |
|  |  |
| 2025-11-19 | 1.0001                      |
|  |  |
| 2025-11-20 | 1.0001                      |
|  |  |
| 2025-11-21 | 1.0001                      |
|  |  |
| 2025-11-24 | 1.0001                      |
|  |  |
| 2025-11-25 | 1.0001                      |
|  |  |
| 2025-11-26 | 1.0001                      |
|  |  |
| 2025-11-28 | 1.0001                      |
|  |  |

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

### Class: Advantage Class

- **Minimum Initial Investment:** $1000000.00

- **Net Assets of Class:** $64958563.51

- **Number of Shares Outstanding:** 64958549.0800

- **Expense Reimbursement/Waiver:** 4464.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-11-03 | 1.0001          |
|  |  |
| 2025-11-04 | 1.0001          |
|  |  |
| 2025-11-05 | 1.0001          |
|  |  |
| 2025-11-06 | 1.0002          |
|  |  |
| 2025-11-07 | 1.0001          |
|  |  |
| 2025-11-10 | 1.0001          |
|  |  |
| 2025-11-11 | 0.0000          |
|  |  |
| 2025-11-12 | 1.0001          |
|  |  |
| 2025-11-13 | 1.0001          |
|  |  |
| 2025-11-14 | 1.0001          |
|  |  |
| 2025-11-17 | 1.0001          |
|  |  |
| 2025-11-18 | 1.0001          |
|  |  |
| 2025-11-19 | 1.0001          |
|  |  |
| 2025-11-20 | 1.0001          |
|  |  |
| 2025-11-21 | 1.0001          |
|  |  |
| 2025-11-24 | 1.0001          |
|  |  |
| 2025-11-25 | 1.0001          |
|  |  |
| 2025-11-26 | 1.0001          |
|  |  |
| 2025-11-28 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-11-03 | $1044124.69               | $635938.45              |
| 2025-11-04 | $207847.73                | $267359.77              |
| 2025-11-05 | $28550.00                 | $354492.48              |
| 2025-11-06 | $1292780.60               | $150598.96              |
| 2025-11-07 | $3035845.47               | $350130.29              |
| 2025-11-10 | $509142.10                | $335306.98              |
| 2025-11-11 | $0.00                     | $0.00                   |
| 2025-11-12 | $352102.82                | $290369.38              |
| 2025-11-13 | $578551.18                | $534378.06              |
| 2025-11-14 | $1526500.00               | $117199.17              |
| 2025-11-17 | $64922.43                 | $128919.80              |
| 2025-11-18 | $126800.00                | $1123309.01             |
| 2025-11-19 | $270339.59                | $375084.61              |
| 2025-11-20 | $596546.06                | $332499.26              |
| 2025-11-21 | $225410.08                | $240678.05              |
| 2025-11-24 | $189600.00                | $146040.70              |
| 2025-11-25 | $392087.59                | $1782701.51             |
| 2025-11-26 | $253000.00                | $437497.04              |
| 2025-11-28 | $335010.00                | $2567159.94             |

**Total Gross Subscriptions (Month):** $11029160.34

**Total Gross Redemptions (Month):** $10169663.46

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-11-03 | 3.7000%           |
| 2025-11-04 | 3.6900%           |
| 2025-11-05 | 3.6700%           |
| 2025-11-06 | 3.6700%           |
| 2025-11-07 | 3.6400%           |
| 2025-11-10 | 3.6300%           |
| 2025-11-11 | 0.0000%           |
| 2025-11-12 | 3.6400%           |
| 2025-11-13 | 3.6400%           |
| 2025-11-14 | 3.6400%           |
| 2025-11-17 | 3.6400%           |
| 2025-11-18 | 3.6400%           |
| 2025-11-19 | 3.6300%           |
| 2025-11-20 | 3.6300%           |
| 2025-11-21 | 3.6200%           |
| 2025-11-24 | 3.6200%           |
| 2025-11-25 | 3.6200%           |
| 2025-11-26 | 3.6300%           |
| 2025-11-28 | 3.6500%           |

**Beneficial/Record Owner Categories**
| Category      | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Broker-dealer |  | 99.8400%         | 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: FSSgAK1AW, C.3 - LEI: N/A, C.5 - Other ID: FSSgAK1AW
- **C.18 - Value (incl. sponsor support):** $65220569.09
- **C.18.a - Value (excl. sponsor support):** $65220569.09
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-12-01
- **C.12 - Maturity Date (WAL):** 2025-12-01
- **C.13 - Final Legal Maturity Date:** 2025-12-01
- **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:** 2025-12-05

**By:** /s/ Chad Hallett

**Name of Signing Officer:** Chad Hallett

**Title of Signing Officer:** Deputy Treasurer