In the province of Quebec les banques populaires (cooperative units) are known as caisses or caisses populaires. Since the text appear to be talking about backoffice services provided to the sector I think it would be safe to translate as "Credit unions" and to keep "caisses" in brackets since it is a unique thing to Quebec.

Here is a quote from the source quoted below:

Credit unions and caisses populaires are co-operative financial institutions owned and controlled by their members. Their ownership and corporate governance are based on co-operative principles, and their main purpose is to provide deposit and loan services to members. In most provinces, each customer is required to become a member of the credit union or caisse populaire. Each member has one vote, regardless of the size of deposit or share capital held.