Data & identity · also called 2P data
Second-party data
Second-party data is another company's first-party data shared directly with you through a partnership, such as an airline sharing audience insights with a hotel chain.
Second-party data sits between first and third party. It was collected by a company from its own customers, making it first-party for them, and then shared with a specific partner under an agreement. There is no open marketplace in the middle: the two parties know each other and agree terms.
Typical examples are co-marketing partnerships: an airline and a hotel group finding overlapping customers, a retailer sharing shopper segments with a brand, or a publisher sharing audience data with a sponsor. Today much second-party collaboration happens in data clean rooms, which let partners match and analyse data without handing over raw customer lists.
Privacy law applies firmly. Under GDPR, sharing personal data with another company needs a lawful basis and transparency; under CCPA / CPRA, it may count as "selling" or "sharing". Contracts should specify permitted uses, retention and security. Done well, second-party data gives the quality of first-party data with more scale; done carelessly, it becomes a compliance liability.
Think of it like this
Second-party data is like a friend lending you their personal address book for a specific party invitation, rather than you buying a phone directory.
An example
A European airline and a car-rental company use a clean room to find 600,000 shared customers, then target rental offers to those booking flights to Lisbon.
Related terms
First-party data
First-party data is information a company collects directly from its own customers or audience, such as purchases, sign-ups, app use and site behaviour, through its own channels.
Third-party data
Third-party data is information about people collected by companies with no direct relationship to them, then aggregated and sold or licensed to advertisers, often as ready-made audience segments.
Data clean room
A data clean room is a secure environment where companies combine and analyse their customer data together, getting aggregated insights or audiences without exposing each other's raw personal data.
Zero-party data
Zero-party data is information a customer intentionally and proactively gives a brand, such as preferences, intentions or quiz answers, rather than data inferred from their behaviour.
GDPR
The GDPR (General Data Protection Regulation) is the European Union's data protection law, applying since May 2018, which governs how organisations collect and use personal data about people in the EU.
Sources: GDPR Article 6: lawfulness of processing, IAB Tech Lab Open Private Join & Activation (clean rooms)