---
title: "Compute Fund Expense Ratios"
method: POST
path: "/v1/tools/compute_fund_expense_ratios"
tags: ["TODO_TAGS_REVIEW", "TODO_AP2_EXPORT_REVIEW"]
---

# Compute Fund Expense Ratios

`POST /v1/tools/compute_fund_expense_ratios`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/compute_fund_expense_ratios`
- Auth: none declared

Computes a fund's gross and net expense ratios and Total Expense Ratio (TER) from SUPPLIED gross expense components (flat amounts or accruals, using the identical accrual conventions as recompute_fund_nav/FN-1) and average net assets, applying any declared fee waivers/caps strictly in a DECLARED order using fixed-point BigInt money math throughout (no float accumulation). Waiver ordering is the substance: the order in which fixed-dollar caps, percent-of-remaining reimbursements, and rate caps apply changes the net expense ratio, so the order is a required declared input, never a house convention, and every waiver's running-balance effect is returned for audit. HARD FENCE: every expense component, average-net-assets figure, and waiver term is supplied and asserted, never fetched (zero-egress); this recomputes the arithmetic over declared inputs and attests THAT, never an opinion on expense accuracy and never a compliance determination. Third entry of the Funds/NAV family (nav-verification-pack) alongside recompute_fund_nav (FN-1) and test_nav_error_materiality (FN-2). 40-Act/UCITS citations informative only.

**Tool URL:** https://ainumbers.co/chaingraph/art-375-compute-fund-expense-ratios.html

## Request body

- object
  - `average_net_assets` unknown, required
  - `fund_id` unknown
  - `gross_expense_components` unknown[], required
    - unknown
  - `period_end` unknown
  - `period_start` unknown
  - `rounding` unknown, required
  - `waivers` unknown[], required
    - unknown

## Response `200`

Successful tool execution result

- object
  - `components` object
    - `average_net_assets` string
    - `gross_expense_components` object[]
      - `amount` string
      - `day_count_convention` string
      - `description` string
    - `gross_expense_total` string
    - `net_expense_total` string
    - `waivers_applied` unknown[]
      - unknown
  - `fence` string
  - `fund_id` string
  - `gross_expense_ratio` string
  - `net_expense_ratio` string
  - `not_proven` object[]
    - `detail` string
    - `item` string
  - `period_end` string
  - `period_start` string
  - `regulatory_framework` string
  - `rounding` object
    - `decimal_places` integer
    - `mode` string
  - `structural_error` string
  - `total_expense_ratio` string

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)