# Credit Suisse First Boston Mortgage Securities Corp. Credit Suisse First Boston Mortgage Securities Corp., Series 2003-21, Class 1A4

Credit Suisse First Boston Mortgage Securities Corp. Credit Suisse First Boston Mortgage Securities Corp., Series 2003-21, Class 1A4 is a security (CUSIP 22541QPB2) tracked across SEC portfolio filings. 1 registered fund positions totaling $23K via N-PORT as of 2026-05-31.

## Summary

- Issuer: Credit Suisse First Boston Mortgage Securities Corp.
- Class: Credit Suisse First Boston Mortgage Securities Corp., Series 2003-21, Class 1A4
- CUSIP: 22541QPB2
- Asset category: ABS-MBS
- 13F holders: 0
- N-PORT fund positions: 1
- N-PORT value: $23K
- N-PORT report: 2026-05-31

## Top fund holders (N-PORT)

| Fund | Registrant | Value | % of fund |
| --- | --- | --- | --- |
| [JPMorgan Core Bond Trust](https://search.stillhousedata.com/fund/S000007337) | JPMorgan Institutional Trust | $23K | 0.05% |

## More

- [This page as markdown (for LLM agents)](https://search.stillhousedata.com/security/22541QPB2.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.