etf-analysis

etf-analysis is a skill for Claude Code from yennanliu/InvestSkill. It costs 61 tokens per session (5,751 once invoked), scanned A, original, MIT.

A due-diligence workflow for exchange-traded funds, or ETFs—funds traded on a stock exchange that hold a basket of investments. It examines costs, tracking, liquidity, holdings, concentration, overlap, distributions, and fund structure.

In plain words
What is it for?
Use it to review an ETF's expense ratio, net asset value, premium or discount, assets, holdings, concentration, distribution history, and fit with other positions.
Why use it?
It brings together the details needed to judge what an ETF owns, how closely it follows its index, and what it may cost or risk. It also compares the fund with its largest holdings.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the us-stock-analysis plugin — 34 skills shipped together

Good fit Use it to review an ETF's expense ratio, net asset value, premium or discount, assets, holdings, concentration, distribution history, and fit with other positions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/yennanliu/investskill/etf-analysis
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add yennanliu/InvestSkill --skill etf-analysis
Clone the repo
git clone --depth 1 https://github.com/yennanliu/InvestSkill

Made for: Claude Code.

Or install us-stock-analysis, the plugin that ships this one along with the rest of its 34 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for etf-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/yennanliu/investskill/etf-analysis/github.svg)](https://agentmods.dev/skills/yennanliu/investskill/etf-analysis)
Your own site
<a href="https://agentmods.dev/skills/yennanliu/investskill/etf-analysis"><img src="https://agentmods.dev/badge/skills/yennanliu/investskill/etf-analysis/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for etf-analysis

Your own site · 80×15
<a href="https://agentmods.dev/skills/yennanliu/investskill/etf-analysis"><img src="https://agentmods.dev/badge/skills/yennanliu/investskill/etf-analysis.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,751 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00061 $0.05751
Opus 5.5 $0.00024 $0.02300
Sonnet 5.5 $0.00012 $0.01150
Haiku 4.5 $0.00006 $0.00575

Measured 5d ago against content hash cfb22d500b69, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

etf-analysis scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/us-stock-analysis/skills/etf-analysis/SKILL.md · 280 lines

How it starts

The opening of the file, as written. The whole thing — 280 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ETF Analysis — What You Actually Own, and What It Costs You

⚠️ Data Verification — Do This Before Any Analysis

Before running any analysis, always retrieve the latest fund data for the ticker:

  1. Fetch current price and NAV — use web search or ask the user for the live price, the fund's net asset value, and the premium/discount to NAV. Never assume a price from training data.
  2. Confirm the fund facts from the issuer — expense ratio, index tracked, AUM, inception date, holdings count, top-10 weights, and distribution history come from the issuer's factsheet and prospectus, not from memory. Fund facts change: expense ratios get cut, indexes get swapped, funds get merged or closed.
  3. State your data source — fill in the Data & Sources header (next section) so the origin, as-of date, retrieval path, and confidence of every figure are explicit at the top of the output.
  4. Flag stale data explicitly — if live data is unavailable, display this warning before proceeding:

⚠️ Live data unavailable. The following analysis uses training-data estimates which may be significantly out of date. Verify all prices and metrics before making any decisions.

Never silently substitute training-data estimates for current fund facts. When in doubt, ask the user to paste the factsheet.


📋 Data & Sources Header — Open Every Output With It

The first thing in the output is this provenance block, filled in — never left as placeholders. It is the standard documented on the Data & Accuracy page and the first thing result-validator looks for:

Data & Sources
  As of:      <date the figures represent, e.g. 2026-06-30>
  Source:     <primary docs — SEC EDGAR 10-K/10-Q, company IR, FRED, exchange data …>
  Retrieval:  <pasted by user | web/tool retrieval | model memory>
  Confidence: <HIGH | MEDIUM | LOW>
  • Retrieval: model memory must be paired with Confidence: LOW — memory is a placeholder until confirmed against a primary source.
  • Mixed sources: list each with its own as-of date rather than blending them.
  • Sources disagree on the same figure (a closing price, a deal term): prefer the primary source (SEC filing, company release, exchange data) over an aggregator, then the most recent dated one. Show both values with their sources and dates, say which you used and why, and never average them.
  • Data the user pasted is reported as pasted by user; do not upgrade its confidence beyond what the user's own source supports.

Read the full file on GitHub · 280 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago Changed · +1 lines cfb22d500b69
  2. 22d ago First seen · 279 lines · 61 tokens per session scan A c5017a6232bf

Subscribe to this mod's changes

etf-analysis is a skill published in the GitHub repository yennanliu/InvestSkill (248 stars, last pushed yesterday), licensed MIT. It adds 61 tokens to every session and 5,751 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-25.

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