Most times investors understand that, as a party to a legal agreement, their name and address has to appear in the agreement.
But, occasionally an investor may contact a company asking why their details are being shown, and even claiming it's a breach of GDPR.
It's not a breach of GDPR, it's a legal requirement, here's why:
Firstly, the name and address of each person needs to be in a contract:
https://seqlegal.com/blog/identifying-the-parties-to-a-contractNext, your Register of Members (i.e. your cap table export) needs to have the name and address of each shareholder:
https://www.legislation.gov.uk/ukpga/2006/46/part/8/chapter/2
"The register ... must be open to the inspection to ... any member of the company without charge"
So your shareholders can, by law, see each other's addresses.
All of which means that, by law, your Shareholders Agreement and other documents need to display the name and address of each party to the agreement.