Portfolio Visualizer backtests the historical performance of a portfolio of stocks/ETFs.
1. What it does
Enter weights and it computes historical return, volatility and max drawdown — answering "how would this allocation have done over the past decade?" with data.
2. Validate allocation
Vary the stock/bond mix and rebalancing cadence to compare outcomes — useful for building an asset-allocation plan, especially for assets with stable patterns like large caps.
⚠️ Limits of backtesting
Past performance doesn't guarantee the future. An allocation optimized for one period may lag in another. Use it to test ideas, and beware overfitting.