# Long-Term US Government Bond Portfolio

Long-Term US Government Bond Portfolio is a registered fund series of NORTHWESTERN MUTUAL SERIES FUND INC (series S000018234). Net assets $120.5M as of 2026-03-31.

## Profile

- Series ID: S000018234
- Registrant: NORTHWESTERN MUTUAL SERIES FUND INC
- LEI: G1NIKRLT4013DJUHQR28
- Net assets: $120.5M
- Total assets: $346.2M
- As of: 2026-03-31

## Advisers

- [Pacific Investment Management Company LLC (Subadvisor)](https://search.stillhousedata.com/firm/104559)
- [Mason Street Advisors, LLC (Advisor)](https://search.stillhousedata.com/firm/114085)

## Top holdings (122 reported)

_Showing 15 of 122 holdings by value._

| Holding | Ticker | Value | % of fund |
| --- | --- | --- | --- |
| [United States Treasury](https://search.stillhousedata.com/security/912810SQ2) | — | $25.5M | 2114.90% |
| [United States Treasury](https://search.stillhousedata.com/security/912810QQ4) | — | $15.5M | 1284.87% |
| [United States Treasury](https://search.stillhousedata.com/security/912810TL2) | — | $13.6M | 1128.42% |
| [United States Treasury](https://search.stillhousedata.com/security/912810UG1) | — | $10.4M | 862.55% |
| [United States Treasury](https://search.stillhousedata.com/security/912810TK4) | — | $7.9M | 658.35% |
| [United States Treasury](https://search.stillhousedata.com/security/912810SF6) | — | $7.6M | 634.43% |
| [United States Treasury](https://search.stillhousedata.com/security/912810SL3) | — | $7.5M | 624.07% |
| [UMBS, TBA](https://search.stillhousedata.com/security/01F060659) | — | $6.9M | 574.40% |
| [United States Treasury](https://search.stillhousedata.com/security/912810ST6) | — | $6.3M | 523.74% |
| [United States Treasury](https://search.stillhousedata.com/security/912810SE9) | — | $3.3M | 273.07% |
| [United States Treasury](https://search.stillhousedata.com/security/912810TJ7) | — | $3.2M | 265.40% |
| [United States Treasury](https://search.stillhousedata.com/security/912810SD1) | — | $2.9M | 243.56% |
| [United States Treasury](https://search.stillhousedata.com/security/912810TS7) | — | $2.7M | 227.95% |
| [United States Treasury](https://search.stillhousedata.com/security/91282CJY8) | — | $2.7M | 227.45% |
| [UMBS, TBA](https://search.stillhousedata.com/security/01F040651) | — | $2.7M | 226.84% |

## Net asset history

| Report date | Net assets |
| --- | --- |
| 2026-03-31 | $120.5M |
| 2025-12-31 | $121.4M |
| 2025-09-30 | $123.0M |
| 2025-06-30 | $122.4M |
| 2025-03-31 | $120.8M |
| 2024-12-31 | $114.4M |
| 2024-09-30 | $125.0M |
| 2024-06-30 | $115.5M |

## More

- [Registrant: NORTHWESTERN MUTUAL SERIES FUND INC](https://search.stillhousedata.com/registrant/742212)
- [This page as markdown (for LLM agents)](https://search.stillhousedata.com/fund/S000018234.md)
- [Search all SEC filings, advisers and people on Adviser Search](https://search.stillhousedata.com/)

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Source: public SEC filing data via Adviser Search (https://search.stillhousedata.com).
Agents: this data is also queryable via MCP tools and read-only SQL — see https://search.stillhousedata.com/llms.txt.