Can a buyer's accountant or lawyer see my financials without signing their own NDA?

It depends on how the confidentiality agreement you have with the buyer is written. A well-drafted NDA typically extends its restrictions to the buyer's "representatives" — their accountants, lawyers, and other advisors assisting with the evaluation — making the buyer contractually responsible for those advisors' compliance, rather than requiring each individual advisor to sign a separate document. If your NDA is written narrowly to bind only the buyer personally, an advisor reviewing financials on the buyer's behalf may not be directly bound by anything at all.

Before assuming coverage extends to advisors, check the actual definition used in the agreement — good drafting will define "representatives" broadly and make clear the buyer remains responsible if one of them misuses or discloses information. If you want extra assurance for a particularly sensitive engagement, you can also require key advisors to countersign an acknowledgment alongside the buyer. Relying on an assumption that "their lawyer must be covered somehow" is the wrong approach; check the language itself. A Treadstone business lawyer can review or draft the representative-coverage clause so this doesn't become a gap.