# EDGAR Filing Document

**Accession Number:** 0001107414
**File Stem:** 0001410368-26-019973
**Filing Date:** 2026-2
**Character Count:** 4818
**Document Hash:** 7de87bad565e519d22d05c0c665e5f92
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-019973.hdr.sgml**: 20260226

**ACCESSION NUMBER**: 0001410368-26-019973

**CONFORMED SUBMISSION TYPE**: NPORT-P

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20251231

**FILED AS OF DATE**: 20260226

**DATE AS OF CHANGE**: 20260226

**PERIOD START**: 20251231

**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:** NPORT-P
- **SEC ACT:** 1940 Act
- **SEC FILE NUMBER:** 811-09819
- **FILM NUMBER:** 26689649

**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 Equity 500 Index Fund (Series ID: S000010695)

| Class ID   | Class Name            | Ticker Symbol   |
|:---|:---|:---|
| C000029581 | Administrative Shares | STFAX           |
| C000029582 | Service Shares        | STBIX           |
| C000029583 | Class R Shares        | SSFRX           |
| C000136665 | Class A               | SSSVX           |
| C000136666 | Class K               | SSSYX           |
| C000136667 | Class I               | SSSWX           |

## Form NPORT-P: Monthly Portfolio Investments Report

### NPORT-P: Part A: General Information

**Item A.1. Information about the Registrant.**

- **a. Name of Registrant:** STATE STREET INSTITUTIONAL INVESTMENT TRUST

- **b. Investment Company Act file number:** 811-09819

- **c. CIK number of Registrant:** 0001107414

- **d. LEI of Registrant:** 549300P1E098W6ES7M39

- **e. Address and telephone number of Registrant.**

  - **Street Address 1:** One Congress Street

  - **City:** Boston

  - **State:** MA

  - **Foreign country:** US

  - **Zip / Postal Code:** 02114

  - **Telephone number:** 617-664-7037

**Item A.2. Information about the Series.**

- **a. Name of Series:** State Street Equity 500 Index Fund

- **b. EDGAR series identifier (if any):** S000010695

- **c. LEI of Series:** 549300H1RTP6FLZEZA60

**Item A.3. Reporting period.**

- **a. Date of fiscal year-end:** 2025-12-31

- **b. Date as of which information is reported:** 2025-12-31

**Item A.4. Final filing**

Does the Fund anticipate that this will be its final filing on Form N-PORT? **No**

### Fund Information

**Total Assets:** $13657507810.48

**Total Liabilities:** $542319.79

**Net Assets:** $13656965490.69

**Monthly Return Information**

| Class               | Month 1 Return (%)   | Month 2 Return (%)   | Month 3 Return (%)   |
|:---|:---|:---|:---|
| Class ID C000029581 | 2.32%                | 0.22%                | 0.05%                |
| Class ID C000029582 | 2.32%                | 0.21%                | 0.04%                |
| Class ID C000029583 | 2.29%                | 0.18%                | 0.01%                |
| Class ID C000136665 | -3.07%               | -5.06%               | -5.22%               |
| Class ID C000136666 | 2.34%                | 0.23%                | 0.06%                |
| Class ID C000136667 | 2.33%                | 0.22%                | 0.04%                |

**Monthly Gains & Losses**

| Period   | Net Realized Gain/Loss   | Net Unrealized Appreciation/Depreciation   |
|:---|:---|:---|
| Month 1  | $7324.17                 | $306620948.58                              |
| Month 2  | $-230566.16              | $32528587.84                               |
| Month 3  | $171872.23               | $-211276182.56                             |

### Schedule of Portfolio Investments

| Name                                       | Title                                      | Identifiers                                   | Payoff Profile   | Asset Category   | Issuer Category   | Country   |   Balance | Units   | Value (USD)     | % of Net Assets   | Maturity Date   | Coupon Type   | Annualized Rate (%)   | Restricted?   |   Fair Value Level | Lending Status   |
|:---|:---|:---|:---|:---|:---|:---|---:|:---|:---|:---|:---|:---|:---|:---|---:|:---|
| State Street Equity 500 Index II Portfolio | State Street Equity 500 Index II Portfolio | CUSIP: 85749T756<br>LEI: 549300IDK82VZN2AFK60 | Long             | EC               | RF                | US        |  22173079 | NS      | $13657507810.48 | 100.00%           |  |  |  | No            |                  1 | On Loan: No      |

### Signature

**Date Signed:** 2026-01-16

**Name of Applicant:** STATE STREET INSTITUTIONAL INVESTMENT TRUST

**Signature:** Arthur Jensen

**Name of Signer:** Arthur Jensen

**Title:** Deputy Treasurer