# Active/Passive Balanced Portfolio

Active/Passive Balanced Portfolio is a registered fund series of NORTHWESTERN MUTUAL SERIES FUND INC (series S000000045). Net assets $1.9B as of 2026-03-31.

## Profile

- Series ID: S000000045
- Registrant: NORTHWESTERN MUTUAL SERIES FUND INC
- LEI: 4F2ZSMZDZU02NP7J8L64
- Net assets: $1.9B
- Total assets: $1.9B
- As of: 2026-03-31
- Type: Fund of funds

## Advisers

- [Mason Street Advisors, LLC (Advisor)](https://search.stillhousedata.com/firm/114085)

## Top holdings (30 reported)

_Showing 15 of 30 holdings by value._

| Holding | Ticker | Value | % of fund |
| --- | --- | --- | --- |
| [Northwestern Mutual Series Fund, Inc. - Select Bond Portfolio](https://search.stillhousedata.com/security/668140759) | — | $484.8M | 2512.65% |
| [iShares Core U.S. Aggregate Bond ETF](https://search.stillhousedata.com/security/464287226) | — | $265.2M | 1374.50% |
| [Northwestern Mutual Series Fund, Inc. - Multi-Sector Bond Portfolio](https://search.stillhousedata.com/security/668140882) | — | $147.0M | 762.16% |
| [State Street SPDR Portfolio Long Term Treasury ETF](https://search.stillhousedata.com/security/78464A664) | — | $97.7M | 506.48% |
| [iShares Core S&P 500 ETF](https://search.stillhousedata.com/security/464287200) | — | $96.5M | 499.97% |
| [Northwestern Mutual Series Fund, Inc. - International Equity Portfolio](https://search.stillhousedata.com/security/668140692) | — | $77.8M | 403.11% |
| [Northwestern Mutual Series Fund, Inc. - Emerging Markets Equity Portfolio](https://search.stillhousedata.com/security/668140502) | — | $72.4M | 375.23% |
| [State Street SPDR Portfolio S&P 400 Mid Cap ETF](https://search.stillhousedata.com/security/78464A847) | — | $67.5M | 349.81% |
| [State Street SPDR Portfolio S&P 600 Small Cap ETF](https://search.stillhousedata.com/security/78468R853) | — | $50.0M | 259.03% |
| [Northwestern Mutual Series Fund, Inc. - International Growth Portfolio](https://search.stillhousedata.com/security/668140684) | — | $46.5M | 240.99% |
| [Northwestern Mutual Series Fund, Inc. - Domestic Equity Portfolio](https://search.stillhousedata.com/security/668140791) | — | $43.4M | 224.96% |
| [Northwestern Mutual Series Fund, Inc. - Focused Appreciation Portfolio](https://search.stillhousedata.com/security/668140775) | — | $43.0M | 222.93% |
| [Northwestern Mutual Series Fund, Inc. - Large Cap Blend Portfolio](https://search.stillhousedata.com/security/668140205) | — | $42.7M | 221.09% |
| [iShares Core MSCI EAFE ETF](https://search.stillhousedata.com/security/46432F842) | — | $41.9M | 216.97% |
| [Invesco S&P 500 Equal Weight ETF](https://search.stillhousedata.com/security/46137V357) | — | $34.4M | 178.23% |

## Net asset history

| Report date | Net assets |
| --- | --- |
| 2026-03-31 | $1.9B |
| 2025-12-31 | $2.0B |
| 2025-09-30 | $2.0B |
| 2025-06-30 | $1.9B |
| 2025-03-31 | $1.9B |
| 2024-12-31 | $1.9B |
| 2024-09-30 | $2.0B |
| 2024-06-30 | $1.9B |

## 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/S000000045.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.