Mandatory and Default Rules in Contract and Commercial Law

William Day, Jonathan Morgan, Andrew Robertson, Katy Barnett

• Publisher: Hart Publishing
• Year: 2026
• Edition: 1
• eBook ISBN:
  9781509971220
• Topic: Law
• Subtopic: Commercial Law
• Index: Law

This collection explores the nature and justification of mandatory rules (which are non-excludable) and default rules (which can be modified or excluded by the parties) in contract and commercial law.

The collection distinguishes between different kinds of mandatory and default rules that govern commercial transactions. It also explores the choice of rule in various situations. Which rules are mandatory, and are there clearly understood and convincing reasons for parties to be denied choice? In the case of default rules, on what basis is the default position selected? The collection also explores the fundamentally important relationship between default rules and interpretation, and, relatedly, between default rules and contractual risk allocation. The collection will be of interest to academics and practitioners working across the field of commercial law.

Table of contents

• Acknowledgements
• Contents
• Contributors
• Table of Cases
• Table of Statutes
• Table of International Instruments
• 1. Mandatory and Default Rules: Issues and Themes
• 2. Default and Mandatory Rules in Commercial Law: A Judicial Perspective
• 3. Default Rules, Interpretation and Risk Allocation
• 4. Party Intention, Default Rules and Contract Theory
• 5. Default Rules in Contract Formation
• 6. Default Terms in Sale of Goods Contracts
• 7. When it’s Mandatory to be ‘Reasonable’: The Nature and Application of Reasonableness under the Unfair Contract Terms Act 1977
• 8. Mandatory Statutory Rules, Consumer Contracts and (Default) Incorporation of Terms
• 9. Frustration Dissected: Mandatory and Default Rules
• 10. Date of Breach as a Sticky Default Rule and the Role of the Court in Assessing Reasonable Mitigatory Measures
• 11. The Express Modification of Contract Law’s Default Remedial Rules
• 12. Three Forms of Default Rules (in the Law of Unjust Enrichment)
• 13. Equity in Commerce: Why Do We Need Default Rules?
• 14. From Mandatory to Default Rules: Trusts in the ‘Commercial’ Context
• Index