Swiss Early Retirement Simulator (Zurich Phase 1)

This application is a financial simulation tool designed for individuals planning for early retirement (FIRE) in Switzerland.

Phase 1 focuses on the post-retirement decumulation phase for a single individual with no dependents living in Canton Zurich.

Features

• Dual Emulation Modes: Compare outcomes using both Historic Returns (using ~100 years of historical S&P 500 and proxy data) and Monte Carlo Simulations side-by-side.
• Swiss Tax Modeling: Accurately models Federal, Cantonal, and Municipal income and wealth taxes for Canton Zurich.
• AHV for Non-Workers: Models mandatory AHV contributions for early retirees before age 65.
• Pillar 2 & 3a Liquidations: Simulates growth and staggered lump-sum withdrawals of Pillar 3a accounts (up to 5) and Pillar 2 vesting accounts, including capital withdrawal taxes.
• Smart Cash Buffer: Optional defensive strategy to spend cash first during market downturns, protecting equities.
• Dynamic Expenses: Optional adjustment to reduce expenses when net worth drops below the starting watermark.
• Configurable Success Criteria: Set target ending net worth (e.g., preserve 50% of inflation-adjusted starting wealth) and calculate probability of success.

Project Structure

├── app.py                  # Streamlit frontend UI
├── src/
│   ├── simulation_engine.py # Core decumulation simulation loop
│   ├── tax_engine.py        # Swiss/Zurich tax calculations
│   └── historic_returns.py  # Historic return data and generators
├── docs/
│   ├── prd_early_retirement_calc.md # Product Requirement Document
│   └── design_doc_early_retirement.md # Technical Design Document
├── requirements.txt         # Python dependencies
└── venv/                    # Python virtual environment (ignored by git)

Getting Started

Prerequisites

• Python 3.11+
• Virtual environment tool (venv)

Installation

1. Clone the repository (once created on GitHub):

   git clone git@github.com:b-maldoca/fi.git
   cd fi

2. Set up the virtual environment and install dependencies:

   python3 -m venv venv
   source venv/bin/activate
   pip install -r requirements.txt

Running the Application

Start the Streamlit app:

streamlit run app.py

The app will open in your default browser, typically at http://localhost:8501.