DIFF13F is a minimal Dash app to explore quarterly 13F filings, view top positions, track changes between quarters, and visualize holdings over time.

• 📊 Explore top positions in a single quarter
• 🔍 Spot largest changes between two quarters
• 📈 Track top positions over time with line plots across multiple quarters
• 💻 Minimal web interface powered by Dash

Make sure Python 3.9+ is installed with pip.

Install the diff13f library:

 pip install git+https://github.com/Noe-AC/diff13f.git

This will add the diff13f command to your PATH.

Python libraries (installed automatically via pip):

• dash and dash-bootstrap-components: the interactive web interface.
• plotly: for plots.
• pandas: data loading and manipulation.
• polars: optional high-performance DataFrame library.
• xmltodict: parsing XML-formatted 13F filings.

1. Launch the app:

    diff13f

2. Import the 13F .txt filings.
3. Explore the data in the app.

To use the app you need complete submission text file (13F filings .txt files). These files are typically named something like 0001037389-25-000034.txt.

You can find filings by looking up the company on the SEC EDGAR website. For example:

• 0001037389 - Renaissance Technologies
• 0001067983 - Berkshire Hathaway
• 0001350694 - Bridgewater Associates
• 0001423053 - Citadel Advisors
• etc. (just take any of these URL and substitute the CIK).

Starting from 2013-q2, SEC 13F filings use XML inside the complete submission text file, which DIFF13F parses reliably.

Earlier filings use a fixed-width format (FWF), harder to parse and not fully supported:

• FWF files for Renaissance Technologies and Bridgewater Associates are partially supported.
• FWF files for Berkshire Hathaway fail to parse and are therefore ignored by the app.

This project is licensed under the MIT License — see the LICENSE file for details.