Pieter's Portfolio Tracker (CSV + Yahoo Finance)

A lightweight, command‑line portfolio tracker that reads your trades from a CSV file and pulls live data (price, dividends, day & month moves) from Yahoo Finance via yfinance.

The banner currently prints “Pieter’s Portfolio Tracker” — feel free to change that string in main().

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Features

• Add stock purchases interactively and auto‑save to a CSV
• Aggregate holdings (total shares, average cost, fees)
• Live snapshot (current price/value, gain/loss, portfolio dividend yield)
• Performance: today’s change and last‑month change (value & %)
• Per‑holding breakdown with purchase history

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Requirements

• Python 3.9+
• Packages: pandas, yfinance

pip install pandas yfinance

Note: yfinance fetches market data from Yahoo Finance and can be rate‑limited. Prices may be delayed and sometimes fields (e.g., dividend info) are missing for certain tickers.

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Quick Start

1. Save the script as portfolio_tracker.py (or keep your file name).

2. Create a virtual env (optional but recommended):

   python -m venv .venv && source .venv/bin/activate  # Windows: .venv\Scripts\activate

3. Install deps:

   pip install pandas yfinance

4. Create an empty CSV named portfolio.csv next to the script, with this header:

   symbol,purchase_date,purchase_price,quantity,fees
   

   Add your first line, for example:

   AAPL,2024-01-15,180.50,5,1.00
   

5. Run:

   python portfolio_tracker.py

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CSV Format

The app reads and writes a single CSV (portfolio.csv) with columns:

column	type	example	notes
symbol	string	AAPL	Use Yahoo Finance tickers. For non‑US markets include the suffix (e.g., NESN.SW, ASML.AS).
purchase_date	date	2024-01-15	Format YYYY-MM-DD.
purchase_price	float	180.50	Price per share in your base currency.
quantity	float	5	Number of shares. Supports decimals.
fees	float	1.00	Commission/fees for that trade.

You can add many rows per ticker; the tracker aggregates them.

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Using the App (Menu)

When you run the script, you’ll see:

Options:
1. Add stock purchase
2. View portfolio with performances
3. Save and exit

• 1. Add stock purchase — prompts you for symbol, date, price, quantity, fees. Instantly saves back to portfolio.csv.
• 2. View portfolio with performances — loads holdings, fetches live data (price, dividends, day & month changes) and prints a summary.
• 3. Save and exit — writes the current in‑memory portfolio to CSV and quits.

Live data is optional in the code: display_portfolio(include_current_prices=True, include_performance=True)

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What the Summary Shows

• Total Invested / Fees / Total Cost — sums across all purchases
• Current Value — price × shares (for holdings where a price is available)
• Total Gain/Loss — absolute and percentage vs total cost
• Expected Annual Dividends — per‑share trailing dividend × total shares
• Portfolio Dividend Yield — expected annual dividends ÷ current value
• Today’s & Monthly Change — value and % (based on recent close data)

Per holding, you’ll also see:

• Total shares, average cost per share
• Current price/value, gain/loss, dividend yield & annual dividend per share
• Today’s and monthly changes (value & %), when available
• Full list of purchases for that ticker

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Project Structure (simple)

.
├── portfolio_tracker.py   # this script (or your filename)
└── portfolio.csv          # your trades live here

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Notes, Tips & Limitations

• Ticker symbols: International tickers often need a suffix (e.g., .AS, .SW, .L). Check Yahoo Finance for the exact symbol.
• Data availability: Some fields from yfinance.Ticker(...).info may be absent; the code falls back to recent history() when needed.
• Delays & currency: Quotes can be delayed. The script assumes your CSV prices and Yahoo quotes are in the same currency.
• Dividends: Uses trailing dividend metrics; forward yields may differ.
• Performance windows: “Today” uses the previous available close; “Monthly” compares first vs last close in the last month window from history().

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Customizing

• Change the CSV file name by editing the PortfolioTracker('portfolio.csv') line in main().
• Adjust the banner text in main().
• Turn off performance metrics: call display_portfolio(include_current_prices=True, include_performance=False).

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