A portfolio built on client data you can't share isn't a portfolio, it's a liability. The user who asked this question is grappling with a real tension: the desire to prove spreadsheet expertise while respecting the confidentiality of foreign client records. That tension isn't a dead end. It's a signal that the standard approach to showcasing work needs to evolve.
The practical answer is straightforward. Interviewers and clients will ask for examples of your work, but they will also understand data privacy constraints. What they want to see is not the raw data itself, they want evidence of your process, your logic, and your ability to transform information into something useful. Share screen captures of your formulas, your layout decisions, or your macro structures, but blur or replace any personally identifiable information. Better yet, build a sample dataset that mirrors the structure of your real work without containing a single real name or phone number. A spreadsheet that demonstrates how you handled a foreign client's data reconciliation is just as convincing when populated with "Client A, City B, Invoice C" as it is with actual records. The skill is in the architecture, not the contents.
This approach does more than protect you and your clients. It signals professionalism. When you present a portfolio that anonymizes data while explaining your methodology, you show that you understand compliance, ethics, and the importance of trust in data work. That is a stronger credential than any raw file could be. We believe the best response to this question is to stop treating your current work as proprietary secrets and start treating it as a template system you can abstract and explain. Build a short document that outlines the problem you solved, the tools you chose, and the outcome for the client, without ever exposing the client. That is how you turn data entry into demonstrable expertise.
Next time you update your resume, attach a link to a simple site or a PDF with two or three sanitized case studies. Include a note that live samples are available under NDA. The interviewer will respect the boundary. More importantly, they will see someone who understands that protecting data is part of the job, not an obstacle to proving you can do it.