TimHanewich.Investing 5.1.0

TimHanewich.Investing

A lightweight .NET library for simulating stock portfolio trading.

Features

• Simulated Trading — Buy and sell stocks at specified prices
• Transaction Logging — Every trade and cash movement is recorded with timestamps
• On-the-Fly Holdings — Current positions and cost basis are computed from the transaction history (no stale state)
• Trade Costs — Configurable per-trade commission that is automatically deducted

Installation

Install from NuGet:

dotnet add package TimHanewich.Investing

Quick Start

using TimHanewich.Investing;
using TimHanewich.Investing.Simulation;

// Create a portfolio and fund it
Portfolio portfolio = new Portfolio();
portfolio.EditCash(100_000.00f);

// Buy and sell stocks
portfolio.Buy("AAPL", 10, 150.00f);
portfolio.Buy("AAPL", 20, 175.00f);
portfolio.Sell("AAPL", 5, 200.00f);

// Check current holdings (computed from transaction log)
foreach (Holding h in portfolio.Holdings())
{
    Console.WriteLine($"{h.Symbol}: {h.Quantity} shares, cost basis per share ${h.CostBasisPerShare:F2}, total position cost ${h.CostBasisTotalPosition:F2}");
}

Usage

Creating a Portfolio

Portfolio portfolio = new Portfolio();
portfolio.TradeCost = 4.95f; // optional commission per trade

Depositing and Withdrawing Cash

portfolio.EditCash(5000f);  // deposit $5,000
portfolio.EditCash(-500f);  // withdraw $500

Cash changes are logged as CashTransaction entries with type CashTransactionType.Edit.

Buying Stocks

portfolio.Buy("AAPL", 10, 150.00f);

This will:

1. Verify you have enough cash
2. Log a HoldingTransaction (Buy)
3. Deduct the cost from your cash balance (logged as CashTransactionType.Transaction)
4. Deduct the trade cost/commission if set (logged as CashTransactionType.Expense)

Selling Stocks

portfolio.Sell("AAPL", 5, 200.00f);

This will:

1. Verify you own enough shares to sell
2. Log a HoldingTransaction (Sell)
3. Credit the proceeds to your cash balance
4. Deduct the trade cost/commission if set

Viewing Holdings

Holdings are computed on-the-fly from the transaction history. No stale state is stored.

Holding[] holdings = portfolio.Holdings();

foreach (Holding h in holdings)
{
    Console.WriteLine($"{h.Symbol}: {h.Quantity} shares");
    Console.WriteLine($"  Cost basis per share: ${h.CostBasisPerShare:F2}");
    Console.WriteLine($"  Total position cost: ${h.CostBasisTotalPosition:F2}");
}

• CostBasisPerShare — weighted average price per share (total cost of all buys ÷ total shares bought)
• CostBasisTotalPosition — total cost of the current position (CostBasisPerShare × Quantity)

Reviewing Transaction History

// Holding (stock) transactions
foreach (HoldingTransaction ht in portfolio.HoldingTransactionLog)
{
    Console.WriteLine($"[{ht.TransactedAt}] {ht.OrderType} {ht.Quantity} {ht.Symbol} @ ${ht.ExecutedPrice:F2}");
}

// Cash transactions
foreach (CashTransaction ct in portfolio.CashTransactionLog)
{
    Console.WriteLine($"[{ct.TransactedAt}] {ct.ChangeType}: ${ct.CashChange:F2}");
}

Full Example

using TimHanewich.Investing;
using TimHanewich.Investing.Simulation;
using Newtonsoft.Json;

Portfolio p = new Portfolio();
p.EditCash(100_000.00f);

p.Buy("MSFT", 10, 100.00f);
p.Buy("MSFT", 20, 200.00f);
Console.WriteLine(JsonConvert.SerializeObject(p.Holdings(), Formatting.Indented));

p.Sell("MSFT", 25, 300.00f);
Console.WriteLine(JsonConvert.SerializeObject(p.Holdings(), Formatting.Indented));

Class Reference

TimHanewich.Investing.Simulation