A knowledge qualifier is wording in a warranty that limits the seller’s exposure to matters within the seller’s actual or constructive knowledge. Common formulations include “to the knowledge of the seller”, “to the best of the seller’s knowledge”, and “after due enquiry.”
The drafting choice between “actual knowledge”, “knowledge after due enquiry”, and “knowledge of any director or senior executive” is significant. “Actual knowledge” of named individuals is the narrowest and most seller-favourable; “after due enquiry” implies an obligation to investigate before signing and is more buyer-favourable.