Fantastic product for individual investors If you like data driven investing and are willing to do the work, Portfolo123 provides all the information you need to construct and trade investment strategies. I've been a client for about 10 years and, for fundamental investing, I haven't found any site that comes close. You can write your own formulas to interpret the data, weight stocks in your portfolio, use your own buy and sell rules, trade weekly, monthly, or however often you think appropriate. You can test your strategies on data going back many years, and they provide articles and a forum for exchange of information to help you learn about factor investing and how to use their site. I wouldn't go anywhere else to manage my money.

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.

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.

Extremely powerful and unique tool Extremely powerful and unique tool. Im not aware of any other like it on the market. Despite having no formal finance background I have decisively beaten my benchmark index for multiple years with real money investing in companies that are off most other people's radar. Once you get used to systematically investing with a model you will wonder how you did it any other way (or how you could do it any other way). The staff is extremely knowledgable and responsive. The user community is generous and supportive. Beyond that, the tool is just fun to research, test theories and play around with.

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.