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A cross-cutting capability used across the buy and sell sides, rather than a single point in the auction chain.
Data & Taxonomy · 2PD

Second-Party Data

Second-party data is another organization's first-party data, shared or sold directly through a partnership "” effectively someone else's owned customer data used with permission.

Updated 2025-07-06 Author Luc Dumont Reading time ~4 min

Key takeaways

  • Second-party data is another company's first-party data, shared directly.
  • It's higher quality and more transparent than third-party data.
  • Partnerships and clean rooms are the usual mechanisms for sharing it.
  • It gained importance as third-party data lost reliability.

First-party data, shared

Second-party data isn't a special kind of data "” it's first-party data with a partner. A retailer might share its purchase data with a complementary brand, or a publisher might share audience data with an advertiser. Because it comes from a known source with a direct user relationship, it's more transparent and reliable than aggregated third-party data.

Partnerships and clean rooms

Second-party arrangements are increasingly executed through data clean rooms, which let two parties match and analyze their data without exposing raw records. This makes privacy-safe second-party collaboration a core post-cookie tactic, especially for retail media and CTV.

At a glance
What it isA partner's first-party data
QualityHigh "” known, direct source
MechanismPartnerships, clean rooms
Versus 3PMore transparent and reliable

Frequently asked questions

What is second-party data?

It's another organization's first-party data shared directly through a partnership "” for example, a publisher sharing audience data with an advertiser.

How is second-party data shared safely?

Increasingly through data clean rooms, which let two parties match and analyze their data without either exposing raw user-level records.