Building My Perfect Portfolio Tool
Fellow investors. Surely I am not the only one who has either found different brokers etc to have clunky or useless portfolio tracking tools? Rarely can you track performance, cash, fees, commissions etc on a consistent basis. Nor can you do a nice portfolio attribution analysis or have a good idea of your overall portfolio risk.

Additionally, having accounts in different places, I have always wanted a tool that can bring all of these together in one tool or series of dashboards. A proper portfolio aggregator.

I have built something like this for a series of fixed income portfolios at work, and am embarking on building something similar for my own personal investments.

My goals:
  • Aggregate my different investments (equities, ETFs, bonds, wine, cash);
  • Track performance and be able to slice and dice by basic fields;
  • Basic risk measures;
  • Cash management tool;
  • Track all fees, commisions.

Any must-haves you would have in such a system? How do your monitor your portfolios?

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Maverick Equity Research's avatar
great idea and project. Must-haves:
1) compare own portfolio or single stocks with S&P500 on a total return basis not just price
2) backtest various portfolios or single stocks versus S&P500 - for example last 10 years or 15 or 20
3) calculate the investment of a fixed sum (10,000) into a certain portfolio for the last 10 years or so ... price return, total return and ideally with the assumption of dividend reinvestment
Porchester ✳️'s avatar
@maverickresearch 100% total return is something I am keen to account for, don't want to ignore those dividends!

Backtest and what-ifs are great tools, but I think they are a bit ambitious at the moment for my project. Those need a lot of historical data in the back-end, which needs maintaining etc. And then building a factor-ish model to account for positions that miss historical data (like recent IPOs) is going to be way too ambitious at this stage.

But agree, these are great ideas and tools I already use at work!
Maverick Equity Research's avatar
@porchester cool ... jep, those are tricky ... with funding I could do them as I know how to and have loads of data and APIs ... but yeah, via own excel & stuff no way
Nathan Worden's avatar
What is your preferred metric (or set of metrics) on a dashboard to measure your portfolio risk?
Porchester ✳️'s avatar
@nathanworden I think all the usual portfolio metrics I use at work will be too ambitious in a first instance. Any Value at Risk or sophisticated stress testing will be too tricky from a computational perspective, I intend on building this tool out initially via Power BI since that is a flexible dashboarding tool but limits some more complex stuff to start.

Though I am hoping to source betas from somewhere, or maybe I can calculate betas, and then do a very basic beta stress test. Say S&P down 10%, if my portfolio beta is 2 then I would be down -20% etc.

Another similar stress test would be moving the entire portfolio to the lowest price from say the last 52 weels, or I could shock price earnings ratios. That should be acheivable.

But in the most simplest case, I want to make sure my portfolio isn't too concentrated. Basic breakdowns by country, sector, strategy.

The key with any good portfolio tool will be how much of the underlying data I can source and in the most simplest way. It will only be as powerful as the data I can get hold of.
delos's avatar
i really appreciate this post/discussion. we're definitely interested in building better portfolio tools here at commonstock!
Porchester ✳️'s avatar
@diggity More than happy to discuss ideas or brainstorm about what you guys are currently working on!



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