Investors in stocks and equity mutual fund know the importance of having a diversified portfolio. For people holding mutual funds, which are typically large collections of different stocks, portfolio diversification can be tricky. First, funds may hold hundreds of stocks and it's not always easy to keep track of them. Second, if an investor holds multiple funds, there may be significant overlaps in their stock holdings, thus hurting portfolio diversification.
This project seeks to help investors with mutual fund portfolio diversification. We use the well-known Treemap information visualization technique to present the stocks held in the different funds owned by a person. We map the relative holding or weight of a stock in a portfolio to the area of that stock's rectangle in the treeemap view. Unfortunately, stocks not owned in funds have $0 value in the portfolio, and thus no area, so they wouldn't appear in the display. We definitely want to show these stocks, because investors may purchase new funds to add these stocks to the portfolio.
Essentially, this challenge can be reduced to the problem of representing 0-valued items in a treemap display. To do so, we created the concept of a Context Treemap, one that shows a distorted treemap view in which 0-valued items are given some proportion of the overall display area. Details of how the technique works can be found in the paper above.
We implement the Context treemap technique in a system called FundExplorer. FundExplorer helps investors examine the different stock holdings in their fund portfolio and explore how the addition of new funds would change the portfolio. Different types of items in the system can be selected. These selections then act as filtering or brushing tools, helping to promote interactive exploration and facilitating a kind of dynamic querying capability.
The figure below shows a screen shot of the FundExplorer system. The large graphical area to the right shows the portfolio view. The three lists ot the left provide, respectively, 1) all available funds, 2) funds meeting filtering criteria, and 3) funds held in the portfolio. The user can specify a different color for each fund to help show where the different funds concentrate in the portfolio.
To get a better feel for how FundExplorer works, please view the 4-minute video of the system that we prepared for the InfoVis 2003 Conference. 92 megabyte MPEG video. The audio narration is very soft, so you may need to turn up your volume.