It's magic ;), nah, in calculations for the field select "Sum", and that should fix it. The other tricky one is the size, in calculations it's set to "highest", and it's also set to not print repeated values, good luck.

>Hi,
>Thank you. I have receive your mail.
>I have tried to create my own report by refering to your, however it doesn't work. It only show the stock of last record and 0 for the rest.
>What mistake I make?
>
>Thank you