Can a seller's knowledge qualifier be limited to just what one specific person knew?

Yes, and whether that's a good idea depends entirely on which side of the deal you're on. Nothing prevents a purchase agreement from defining "seller's knowledge" as the actual knowledge of one named individual, rather than a broader group — but doing so significantly narrows what the representation actually protects the buyer against, since only that one person's awareness of a problem matters, regardless of what anyone else at the business genuinely knew.

Buyers generally resist a single-person knowledge qualifier and push instead for a defined group of relevant individuals — key officers, the controller, department heads with direct knowledge of specific areas — precisely because concentrating knowledge in one person creates an obvious gap: something the bookkeeper or operations manager clearly knew, but the named individual didn't, could fall entirely outside the representation. Sellers, especially a sole owner-operator selling their own business, sometimes prefer the narrower version because it's simpler and reflects that they genuinely are the only person with relevant knowledge.

Whether a single-person qualifier is appropriate for your specific deal depends on how the business is actually run and who really holds relevant information — worth discussing directly with a Treadstone business lawyer before agreeing to either version.