# EDGAR Filing Document

**Accession Number:** 0001107414
**File Stem:** 0001193125-26-229213
**Filing Date:** 2026-5
**Character Count:** 3149
**Document Hash:** 2f421b461978e678fe3e08fe655c21db
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-229213.hdr.sgml**: 20260519

**ACCESSION NUMBER**: 0001193125-26-229213

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 10

**FILED AS OF DATE**: 20260519

**DATE AS OF CHANGE**: 20260518

**EFFECTIVENESS DATE**: 20260519

**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:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-30810
- **FILM NUMBER:** 26995315

**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 Prime Retail Reserves Money Market Fund (Series ID: S000101207)

---

|  |  |  |
|:---|:---|:---|
| Class Name            | Ticker Symbol | Class ID   |
| Advisory Class        | PRDXX         | C000271297 |
| Advantage Class       | PAVXX         | C000271298 |
| Cash Management Class | PCMXX         | C000271299 |
| Capital Class         | PCPXX         | C000271300 |
| Agency Class          | PRAXX         | C000271301 |

---

## Series and Classes Contracts Data

### State Street Federal Prime Retail Reserves Money Market Fund (Series ID: S000101207)

| Class ID   | Class Name            | Ticker Symbol   |
|:---|:---|:---|
| C000271297 | Advisory Class        | PRDXX           |
| C000271298 | Advantage Class       | PAVXX           |
| C000271299 | Cash Management Class | PCMXX           |
| C000271300 | Capital Class         | PCPXX           |
| C000271301 | Agency Class          | PRAXX           |

?xml version='1.0' encoding='ASCII'? STATE STREET INSTITUTIONAL INVESTMENT TRUST

------

Filed pursuant to 497(e) and 497(k)

File Nos. 333-30810 and 811- 09819

#### State Street Institutional Investment Trust

#### State Street Federal Prime Retail Reserves Money Market Fund
(the "Fund")

Cash Management Class (PCMXX)

Capital Class (PCPXX)

Agency Class (PRAXX)

Advisory Class (PRDXX)

Advantage Class (PAVXX)

*Supplement dated May 19, 2026 to the Prospectus, Summary Prospectus and Statement of Additional Information ("SAI"), each dated March 13, 2026, as may be supplemented from time to time* 

#### Effective immediately, the name of the Fund will change. Accordingly,

#### effective immediately, all references to the Fund's name in the Prospectus,

#### Summary Prospectus and SAI will be updated as follows:

---

| | |
|:---|:---|
| **Current Fund Name** | **New Fund Name** |
| State Street Federal Prime Retail Reserves Money Market Fund | State Street Prime Retail Reserves Money Market Fund |

---

#### This change will not result in any changes to the Fund's Investment Objective,

#### Principal Investment Strategies or Principal Risks of Investing in the Fund.

#### PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE
051926SUPP1