Portfolio123 is a game-changer for… Portfolio123 is a game-changer for stock investors, providing a powerful platform for the design, simulation, and deployment of quantitative financial models. It also has stock screening, charting (including YChart style), trading (via Interactive Brokers and Tradier), macro economics charting, watchlists, an earnings center, cross-section series plotting, external data importer, a data API, stock news, stock summary snapshots, stock comparison tool, sector/Industry performance, fundamental and estimate summaries, a user forum and more (really). In the near future, machine learning will be supported. It's not just another retail-level tool; it's the only one that I’ve found to work in practice. To find something better, I suspect you'd have to go professional and spend significantly more. I've been a loyal subscriber for over a decade, which speaks volumes about its effectiveness. Is there a downside? Sure, building successful trading models is hard work, but with dedication and focus, it's possible to be successful. Whether you're researching stocks, building and simulating quantitative models, or managing accounts, Portfolio123 has what you need.

More Fun Than Video Games! I Joined P123 Apr 28, 2004, and I have been Investing in systems I developed ever sense then. I currently am receiving 60% of my family annual income from my investments. P123 is more fun than video games! I LOVE it! Denny Halwes

Excellent site for backtesting equity trading strategies Excellent site for testing stock and ETF trading strategies. P123 provides a thorough point-in-time database with a powerful and flexible engine to simulate backtests of systems. And they integrate with Interactive Brokers to automate applying those strategies to live trading.

Highly recommended They make a great product and offer a good service. They are responsive. It takes time to learn their tools and how to navigate their website which is no different than any other comparable site except that you are doing far less coding from scratch and more actual thinking and developing trading models.

Very flexible stock screening and backtesting platform This is the best and most flexible platform for stock and ETF screening, ranking and backtesting I know. With main focus on fundamentals, you can test, combine and vary hundreds of parameters. No programming knowledge required. One restriction: Portfolio123 does not support intraday trading.