Your broker lies
about your returns
Simple P&L percentages get diluted every time you deposit or withdraw. Promethean calculates your true time-weighted return — so you know exactly how your investments actually performed.
No spam. We'll notify you when we launch.
The number your broker shows you is wrong
Every deposit dilutes your displayed return. Every withdrawal inflates it. Here's what that looks like in practice.
Example: You invest $10,000 and it grows 30% to $13,000.
Great. Then you deposit another $20,000. Your portfolio is now $33,000
with $3,000 profit on $30,000 invested — your broker shows
+10%. But your investment skill earned +30%.
Promethean shows you the 30%.
Built for investors who want the truth
Modified Dietz TWR
Proper time-weighted returns that account for every deposit, withdrawal, and their exact timing.
Copy Trader Tracking
Finally see real performance of your copy trading. No platform does this properly — we do.
Multi-Broker Support
Connect eToro, Trading 212, IBKR, and more. One dashboard for your entire portfolio.
Historical Accuracy
Import your full transaction history. See how your returns actually evolved over time, not just today's snapshot.
Your Data, Your Control
Read-only broker connections. We never execute trades or move your money. Privacy-first architecture.
True Cost Tracking
Spreads, overnight fees, currency conversion — all the hidden costs that eat your returns, made visible.
Roadmap
eToro Integration
Full portfolio import, TWR calculations, and copy trader performance tracking.
Multi-Broker Dashboard
Trading 212, Interactive Brokers, and manual CSV import support.
Benchmarking & Insights
Compare your returns against S&P 500, your copy traders, and custom benchmarks.
Tax Reporting
Automated capital gains calculations and tax-loss harvesting suggestions.
Stop guessing. Start knowing.
Join the waitlist for early access.