How do I do this please?

There doesn't appear to be any way of achieving this from the standard Product Valuation Reports.

Retrospective Valuation almost works but it values stock from 01/01/1980 up to the date you put in. That would give you a rolled up total for each month.

Give it a go. It might be what you (your company) are looking for.

Hi Ann,

I have come up with a way of doing this - took me some effort! I'll send you a friend request to discuss offline