---
title: "13F filer concentration summary"
method: GET
path: "/13f/filers/{bw_filer_id}/concentration"
tags: ["13F Filers"]
---

# 13F filer concentration summary

`GET /13f/filers/{bw_filer_id}/concentration`

## Request

- Base URL: `https://riskmodels.app/api`
- URL: `https://riskmodels.app/api/13f/filers/{bw_filer_id}/concentration`
- Auth: HTTP bearer

Quarter-end concentration panel from per-filer ds_portfolio.zarr. Returns median and latest effective N, top-5 / top-10 weight share, and weight HHI over an optional date window (same underlying series as /portfolio, summarized for diligence).

## Path parameters

- `bw_filer_id` string, required

## Query parameters

- `start_date` string, date
- `end_date` string, date

## Response `200`

Concentration summary (median + latest).

- object

## Other responses

- `402`: Insufficient prepaid balance.
- `404`: Filer not found, or no concentration panel available.
- `429`: Rate limit exceeded.

---

[API](https://skmtc.dev/riskmodels/apis/riskmodels-api.md) · [All operations](https://skmtc.dev/riskmodels/apis/riskmodels-api/llms.txt) · [OpenAPI document](https://skmtc.dev/riskmodels/apis/riskmodels-api/revisions/1a034cad408a?raw)