Hi HN,

I’m Noah. Before building this project, I worked as a Senior Data Engineer at a top-10 global investment bank, where I focused on large-scale financial data pipelines and analytics systems.

I’ve always found it surprisingly difficult to understand my own long-term investment performance across multiple accounts (401k, IRA, taxable). Each brokerage calculates returns differently, cash flows distort performance numbers, and spreadsheets tend to break as soon as positions, splits, or dividends get complex.

So I started building YieldMirror, a portfolio analytics engine that unifies data from multiple accounts (via CSV) and computes performance and risk using a consistent methodology. The engine also generates an AI-written report summarizing the results in plain English.

What the engine computes • Time-Weighted Return (TWR) • Money-Weighted Return / IRR • CAGR over any window • Volatility, max drawdown, Sharpe, Sortino, Calmar • Benchmark comparison (S&P 500) • Alpha, beta, correlation, information ratio • Position-level contribution and concentration risk • AI-generated summary of performance, risk, and attribution

Live example

Here’s a public report generated by the engine using my own data: https://www.yieldmirror.app/share/i93h85l_Mt

Try the engine

I released a free performance calculator so people can test the engine with their own CSV files: https://www.yieldmirror.app/

The full multi-account app (with dashboards, health reports, and ongoing analytics) is still a work in progress, but the analytics core is complete. I’d love feedback on the methodology, the report UX, the benchmarks, and any metrics you feel are missing.

Happy to answer technical questions about the calculations, data model, or design decisions.

Noah