GLBA is a requirement for financial institutions and their service providers who are permitted access to their customer information through the provision of services directly to the institution. Any vendor a financial institution permits to have access to nonpublic personal information would fall under the scope of GLBA requirements. Per 16 C.F.R. 313.3(n)
Nonpublic personal information means:
Personally identifiable financial information (see 16 C.F.R. 313.3(o) for definition and examples); and Any list, description, or other grouping of consumers (and publicly available information pertaining to them) that is derived using any personally identifiable financial information that is not publicly available.
Nonpublic personal information does not include:
Publicly available information, except as included on a list described in paragraph (n)(1)(ii) of this section; or Any list, description, or other grouping of consumers (and publicly available information pertaining to them) that is derived without using any personally identifiable financial information that is not publicly available.
https://www.ecfr.gov/current/title-16/chapter-I/subchapter-C/part-313
The questions then I would ask internally to your product owners would be, will the service provider in question be permitted access to nonpublic personal information as defined by the linked section.
It would be great to hear from any FI's who would like to share any guidance used to assist in defining and evaluating service providers who fall under GLBA requirements.