A joint defense agreement memorializes the common interest arrangement, identifying the participants, the scope of shared information, confidentiality obligations, and what happens if interests later diverge or a party settles.
Written agreements are not universally required but substantially strengthen the privilege claim.
Alternative Names:
JDA, Common Interest Agreement
Why it Matters?
These agreements are standard in multi-defendant product, construction, and mass tort litigation, and their most important provisions address exit. A party that settles and turns adverse retains knowledge of the shared material, so the agreement should address continuing confidentiality and whether the departing party may use what it learned. Agreements that only cover information sharing without addressing divergence create problems at exactly the moment they matter.
Frequently Confused with
Related terms
Frequently asked questions
Must a joint defense agreement be in writing?
What happens when a participant settles?
