---
title: "Effective Number of Assets"
method: POST
path: "/portfolios/analysis/effective-number-of-assets"
tags: ["Portfolio Analysis"]
---

# Effective Number of Assets

`POST /portfolios/analysis/effective-number-of-assets`

## Request

- Base URL: `https://api.portfoliooptimizer.io/v1`
- URL: `https://api.portfoliooptimizer.io/v1/portfolios/analysis/effective-number-of-assets`
- Auth: API key in header `X-API-Key`

Compute the effective number of assets of a portfolio.

References
* [Steven Strongin, Beating Benchmarks — A Stockpicker's Reality: Part 2, Goldman Sachs, Nov. 30, 1999](https://www.gspublishing.com/content/research/en/reports/1999/11/30/09027316-5afb-11d7-855c-ef4fa3b4f04c.pdf)

## Request body

- object
  - `portfolios` object[], required
    - `assets` integer, required: The number of assets
    - `assetsWeights` number[], required: assetsWeights[i] is the weight of the i-th asset in the portfolio, in percentage

## Response `200`

OK

- object
  - `portfolios` object[], required
    - `portfolioEffectiveNumberOfAssets` number, required: The effective number of assets of the portfolio

## Changes

- **2026-02-08** `ac51d393c9a9`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/portfoliooptimizer/apis/portfolio-optimizer/changes/portfolios/analysis/effective-number-of-assets/post.md)

---

[API](https://skmtc.dev/portfoliooptimizer/apis/portfolio-optimizer.md) - [All operations](https://skmtc.dev/portfoliooptimizer/apis/portfolio-optimizer/llms.txt) - [OpenAPI document](https://skmtc.dev/portfoliooptimizer/apis/portfolio-optimizer/revisions/9d075aa717bf?raw)