A summary field with the "total of" option selected placed in the right part of your report will do this. Look up Summary fields in filemaker's help system to read up on how they work.
Thank you for your post.
The answer provided by PhilModJunk is correct (Thank you!). However, here is some additional information that may help.
In "Manage -> Database...", create a new field "TOTAL AMOUNT" that is a Summary field, and it is a Total of "Total_Amt_Invested".
On your layout, create a Sub-Summary section that is sorted by "Individual" field. Place the "Individual" field in this section along with the newly created TOTAL AMOUNT Summary field. When you sort by the "Individual" field, you will see the first list layout.
Below the Sub-Summary section, create a Grand Summary section. In this section, also place the TOTAL AMOUNT Summary field. This will then display a Grand Total for the entire found set. Remove any Body section, and your output will look something like:
Barbara Walters $90,000
Herbert Hoover $60,000
John Doe $125,000
Susie Q $50,000
Let me know if you need clarification for any of the above steps.