sec13f-data-format

A guide to the tab-separated files used in SEC Form 13-F filings, which show quarterly snapshots of certain institutional investment holdings.

In plain words
What is it for?
It is for reading COVERPAGE.tsv and INFOTABLE.tsv files, identifying fund filings, linking accession numbers, and examining reported holdings.
Why use it?
It explains how filing metadata connects to detailed holdings, so analysis can use the right records and reporting periods.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/cxcscmu/skilllearnbench/sec13f-data-format
Any agent
npx skills add cxcscmu/SkillLearnBench --skill sec13f-data-format
Clone the repo
git clone --depth 1 https://github.com/cxcscmu/SkillLearnBench

Made for: Claude Code, Codex.

Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,281 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00025 $0.01281
Opus 5 $0.00013 $0.00641
Sonnet 5 $0.00005 $0.00256
Haiku 4.5 $0.00003 $0.00128

Measured 3d ago against content hash 9947748547f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sec13f-data-format 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 3d 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.

skills/b1-one-shot-claude-haiku-4-5/financial-analysis/sec13f-data-format/SKILL.md · 148 lines

How it starts

The opening of the file, as written. The whole thing — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SEC 13-F Data Format and Structure

Overview

SEC 13-F filings provide quarterly snapshots of large institutional investment holdings. The data is distributed as tab-separated value (TSV) files organized by reporting quarters.

Key Data Files

COVERPAGE.tsv

Purpose: Fund/Manager information and filing metadata Key Columns:

  • ACCESSION_NUMBER: Unique identifier for the filing (use to link with holdings)
  • FILINGMANAGER_NAME: Name of the fund or investment manager
  • REPORTCALENDARORQUARTER: Reporting date (e.g., "30-JUN-2025")
  • DATEREPORTED: When the filing was reported
  • REPORTTYPE: Type of 13-F report

Usage Example:

import pandas as pd

# Load fund information
coverpage = pd.read_csv('/root/2025-q3/COVERPAGE.tsv', sep='\t')

# Find a specific fund by name
fund_info = coverpage[coverpage['FILINGMANAGER_NAME'].str.contains('Renaissance', case=False, na=False)]
accession_number = fund_info['ACCESSION_NUMBER'].values[0]

INFOTABLE.tsv

Purpose: Detailed holdings data for all funds Key Columns:

  • ACCESSION_NUMBER: Links to the fund (from COVERPAGE)
  • NAMEOFISSUER: Company name of the stock
  • CUSIP: Committee on Uniform Security Identification Procedures code (unique stock identifier)
  • VALUE: Market value of holdings in thousands (USD)
  • SSHPRNAMT: Number of shares held (integer)
  • SSHPRNAMTTYPE: Share amount type (usually "SH" for shares)

Usage Example:

# Load all holdings
holdings = pd.read_csv('/root/2025-q3/INFOTABLE.tsv', sep='\t')

# Get holdings for a specific fund
fund_holdings = holdings[holdings['ACCESSION_NUMBER'] == 'specific_accession_number']

# Get count of stocks held
stock_count = len(fund_holdings)

# Find a specific stock
palantir = holdings[holdings['NAMEOFISSUER'].str.contains('PALANTIR', case=False, na=False)]

SUMMARYPAGE.tsv

Purpose: Summary-level information per fund Key Columns:

  • ACCESSION_NUMBER: Fund identifier
  • TABLE_OF_CONTENTS: Summary metadata
  • Other aggregate information

Read the full file on GitHub · 148 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. 3d ago First seen · 148 lines · 25 tokens per session scan A 9947748547f0

Subscribe to this mod's changes

sec13f-data-format is a skill published in the GitHub repository cxcscmu/SkillLearnBench (82 stars, last pushed 1mo ago), licensed MIT. It adds 25 tokens to every session and 1,281 once invoked, about $0.0001 per session on Opus 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 2026-08-30.

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