HI Mark and Jonelle,
You are trying to create a chart similar to this one, made in Numbers '09 (for Mac):

Table 1, feeding the chart is a two column table with one Header Row and one Header Column.
The stock symbols, entered in column A, will appear in the chart's legend, indicating the colour used to represent each stock.
The amount (in whatever unit you are measuring this and wish to compare) is entered in column B. Note that these are NOT percentages. The full circle of a pie chart is ALWAYS 100%. Numbers will calculate the percentage of the total represented by each number in this list, and display that percentage on the chart.
To make the chart:
Enter the list of symbols in column A (must be a Header Column).
Enter the quantity ($ value?) of your holdings for each stock in column B (Must be in non-header cells and on the rows matching each symbol).
Select the values in column B (see blue selection box in image above)
--Click the Charts button in the toolbar (Numbers '09)
--In the option bar that appears (Numbers for iOS) tap Create Chart
Click/Tap the pie chart in the list of chart types.
Result shown is from Numbers '09. I have changes only the width of the text box holding the legend (to force the legend items into a vertical list) and moved the legend from below the chart to the position shown.
I suspect you will find a difference between the list of steps above and the steps you followed in creating the chart.
Regards,
Barry