Have you considered the impact of your corporation's bank?
To have an immediate impact, consider the bank that your corporation uses. Maybe you can't move banks without running a procurement.
Perhaps you need a range of banks to meet different needs. This would be a good way to start a relationship based on a smaller need: FX only and, in time, increase this to product lines and, finally, cash management.
Start the conversation over lunch (we learn a lot simply by sharing experiences with each other) or when doing your annual planning or reviewing the sustainability policy. Alternatively, you can have a look at Dan Sherrard-Smith with Mothertree. I have no affiliation other than my personal appreciation of how Dan brings the topic to the table; namely MotherTree works with values-led businesses to go green and save money on the biggest source of carbon emissions: banks & pensions.
Do you have any other suggested resources to help a company procure a sustainable bank or how to engage with their existing bank on ESG? Feel welcome to add your experience.