About PortfolioAutopsy

PortfolioAutopsy is a free risk check for people who manage their own investments. You type your holdings or upload your broker's positions file, and it shows how your exact mix behaved through every market since 1999: the worst 12-month stretch, the deepest drawdown, your odds of losing money over one, three and five years, and which changes you control would lower those numbers.

Most portfolio tools help you find returns. This one helps you see risk before the market shows it to you. The Crisis Replays tab tests that claim in public: it runs the same analysis as of the day before four real market events, using only data available that day, and shows what happened next. One of those replays is a year when the warning did not come true.

Who built it

I'm Cooper Brown, a junior at the University of Southern California studying Health and the Human Sciences with a minor in Business Finance. I built PortfolioAutopsy because the numbers that matter most to a self-directed investor (how far could this fall, and for how long) are the hardest ones to find in a brokerage app.

How it works

• Daily adjusted prices for 1,300+ stocks, ETFs and mutual funds, back to 1999 where they exist.
• Your holdings and amounts never leave your browser. The math runs on your device.
• Every data refresh runs quality checks for split glitches, stale tickers and short histories, and the core math is checked against an independent implementation. Results are listed under "Receipts" in the app.

What it is not

It is not investment advice, it does not connect to your accounts, and it cannot place trades. It applies today's weights to past markets. That shows what your mix has been capable of, not what it will do next.

Questions or feedback: coopermb@usc.edu