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X12

Multi-party collaboration

Reviewed by LazyQS Editorial·Last reviewed: 2026-02-19

Plain English Explanation

X12 establishes a multi-party collaborative structure where two or more parties work together under a collaboration agreement coordinated with their individual NEC contracts. Under X12, a Core Group meets regularly to manage the project collectively, with decisions made on a collaborative basis.

X12 is associated with alliance contracting and integrated project delivery models. It is used on complex infrastructure, frameworks, and major programmes where multiple clients, contractors, and subcontractors need to be closely integrated. X12 promotes shared risk and reward across the collaborative entity.

X12 does not replace the individual NEC contracts — each party still has their own contract with the Client — but it adds an overarching collaborative governance layer.

Key Takeaway

X12 collaboration governance is resource-intensive — price the Core Group participation cost into your bid and ensure you understand what commercially sensitive information you will be required to share before committing.

What This Means for Subcontractors

If you are included in an X12 collaboration, you are part of the Core Group and have obligations to participate in collaborative governance. This can be resource-intensive. Understand what decisions the Core Group makes, what information you will need to share, and how the pain/gain mechanism operates across the alliance before pricing.

Common Risks & Disputes

  • 1The collaborative governance structure being more time-consuming and costly than anticipated
  • 2Decision-making within the Core Group being slow or contested, delaying the project
  • 3Information sharing requirements revealing commercially sensitive data
  • 4The pain/gain allocation across the X12 partners being disputed at completion
  • 5Individual parties defaulting on their X12 obligations, undermining the collaborative structure

Sources

  1. NEC4 ECC Secondary Option X12— NEC4 ECC
  2. RICS Guidance Note: Collaborative Contracting and Alliance Structures Under NEC4— RICS
  3. ICE Guidance: Multi-Party Collaboration and Core Group Governance in NEC4— ICE

Related Clauses

Option C

Target contract with Activity Schedule

Target cost with Activity Schedule — often used alongside X12 with a shared pain/gain mechanism

Option D

Target contract with Bill of Quantities

Target cost with BoQ — similarly used in alliance/collaboration models

Continue Learning

Category Overview

Back to X Clauses (Secondary Options)

Adjacent Clauses

X11 Termination by the Client on noticeX13 Performance bond

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