GEVA indicator for scope 3 expect category 15?

Hello, we are a financial institution (consumer loans) without any category 15 emissions. We would like to set a target for our scope 1, 2. and scope 3 : on our value chain, wastes, commuting, etc representing at least 67% of our scope 3 emissions.

My question is regarding GEVA : is there any reference to how the GEVA indicator is calculated for a financial institution ?

Thank you