This has nothing to do with development, but whatever.
I’ve been playing around with tools and methods for portfolio management. I’m no investment whiz, and I don’t have the time to actively track individual company performance, so my portfolio contains only simple Schwab index ETFs with low expense ratios. When portfolio rebalancing time comes around, though, I try to get the job done as quickly and efficiently as possible while staying on track.
One of the best tools I’ve found for portfolio rebalancing is the Optimal lazy portfolio rebalancing calculator, written by Albert Mao. This calculator lets you figure out how much money to allocate to each stock in your portfolio given a target allocation percentage, without having to sell any over-weighted assets.
I have put together a template Google Spreadsheet that attempts to simplify this process as much as possible. On the right side of the spreadsheet, you can see current ask and bid price, which are automagically pulled from Yahoo! Finance API and Google Finance Spreadsheet API, respectively. These values are forwarded over to the columns on the left side of the spreadsheet.
To get your rebalancing calculation:
- Enter in your current porfolio values for each stock
- Adjust your asset allocation percentages if needed
- Copy the left 4 columns of the template into the textbox on the rebalancing calculator and hit Recalculate.
To track this information over time, I make side-by-side (before and after) charts on each rebalancing date using the left chart in the spreadsheet, with the Value column reflecting the before and after values for each transaction.
- Optimal lazy portfolio rebalancing calculator by Albert Mao: http://optimalrebalancing.tk/index.html
- Investment Rebalancing Template: https://docs.google.com/spreadsheet/ccc?key=0Ah69vkwClBc-dFhUOUVCTTlwaXlEdDYxUnBqeUVrcUE
- Yahoo! Finance API cheat sheet: http://www.gummy-stuff.org/Yahoo-data.htm
- Investment primer: http://www.iwillteachyoutoberich.com/