sum cell with multiple criteria using do loop and a function

[beija]

Hi everybody,

if someone can help me: I try to sum amounts based on 3 criteria and show the resulting sums in another location (same or not worksheet/workbook). With the example below it will be easier to explain:
I have this (thousand rows):
Investor Name Exchange where the investor intervene Financial products bought by the investor Amounts purchased
A London bonds 10
A London bonds 10
A London bonds 10
A London stocks 10
A NY bonds 10
A NY stocks 10
A Paris stocks 10
A Paris stocks 10
B London bonds 10
B London bonds 10
B London stocks 10

I want this:
Investor Name Exchange where the investor intervene Financial products bought by the investor Amounts purchased
A London bonds 30
A London stocks 10
A NY bonds 10
A NY stocks 10
A Paris stocks 20
B London bonds 20
B London stocks 10

I used a long time ago a macro which execute this using at the cell level ( sheetname.cells(i,j) ) a do loop, if condition and a function that sum the amount purchased, because I would like the caracteristics of each investor show next to the sum. Unfortunately I don't remember the code, I tried different ways but I missed something.

Thanks for your help