RSA 78-B:11 — Taxpayer Records. –

Every buyer and seller of real estate shall:
I. Keep such records as may be necessary to determine the amount of his liability under this chapter.
II. Preserve such records for the period of 3 years or until any litigation or prosecution under this chapter is finally determined.
III. Make such records available for inspection by the commissioner or his authorized agents, upon demand, at reasonable times during regular business hours.