How it works in a data room
Before upload, the seller swaps identifiers such as names, employee numbers or customer account IDs for codes, for example “Employee 0147” or “Customer C-22”. The key linking codes to real identities stays with the seller, outside the room or in a folder nobody else can open. Bidders can still analyze patterns, such as pay distribution or customer churn, without knowing who is who. When the winning bidder needs identities later, the seller can release the key for selected records.
Why it matters in a deal
Under the GDPR, pseudonymized data is still personal data, because it can be re-identified with the key, but it is recognized as a safeguard that lowers risk. True anonymization goes further and is often impractical for detailed diligence. Pseudonymization is the common middle path: useful analysis for bidders, lower exposure for the seller. Small datasets need extra care, since a unique job title or location can identify someone even without a name.
Example
A lender selling a portfolio of consumer loans uploads a data tape where borrower names and addresses are replaced by loan codes and regions. Bidders price the portfolio from payment histories and balances. After signing, the buyer receives the key for the transfer of servicing. The Netherlands guide covers data handling there.