Build 13-F Hedge Fund Inflow Analyzer

Goal

Build an application to analyze SEC 13-F filings from hedge funds to identify stocks with higher-than-average inflows in a given quarter.

Research Summary

Data Source

• SEC Form 13F Data Sets (official bulk downloads)
• URL: https://www.sec.gov/data-research/sec-markets-data/form-13f-data-sets
• Pre-flattened TSV files (no XML parsing needed)
• ~70-85 MB per quarter (compressed), ~5000 filers included

Storage Estimates

| Period | Compressed | Uncompressed |
|--------|------------|--------------|
| 1 quarter | ~80 MB | ~400 MB |
| 8 quarters | ~640 MB | ~3 GB |
| Full history (2013+) | ~4 GB | ~20 GB |

Data Format (inside ZIP)

• SUBMISSION.tsv - filing metadata
• INFOTABLE.tsv - holdings data
• COVERPAGE.tsv - manager info

Proposed Architecture

┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│   1. DOWNLOADER │ --> │   2. LOADER     │ --> │   3. ANALYZER   │
│  (fetch ZIPs)   │     │ (TSV → SQLite)  │     │  (run queries)  │
└─────────────────┘     └─────────────────┘     └─────────────────┘
        │                       │
        v                       v
   data/zips/              SQLite DB

Stage 1: Downloader

• Fetch quarterly ZIP files from SEC
• Store in data/zips/
• Track download state in manifest

Stage 2: Loader

• Extract TSV files from ZIPs
• Load into SQLite database
• Compute quarter-over-quarter changes

Stage 3: Analyzer

• Query DB for aggregated inflows per stock
• Compute historical averages and z-scores
• Output ranked list of anomalous inflows

Analysis Logic

"Higher-than-average inflows" defined as:

1. Per stock per quarter: Sum all position increases across tracked funds
2. Historical baseline: Same stock's average quarterly inflow over past 8 quarters
3. Anomaly detection: Flag stocks where currentInflow > mean + 1.5 * stddev

Tech Stack

• TypeScript (fits existing monorepo)
• SQLite (local analysis, no server needed)
• Commander.js (CLI)

Open Questions

• [ ] Integrate into investing-toolkit monorepo or standalone?
• [ ] Which funds to track? (Top N by AUM, all filers, custom list?)
• [ ] Output format preferences (CSV, JSON, web UI?)

Tasks

• [ ] Set up project structure
• [ ] Implement downloader (Stage 1)
• [ ] Implement loader (Stage 2)
• [ ] Implement analyzer (Stage 3)
• [ ] Add CLI commands
• [ ] Add tests