N.H. Rev. Stat. Ann. § 282-A:72

If the base period wages of an individual include wages from one or more reimbursing employers and one or more additional employers, reimburser or taxpayer, benefits paid to such individual shall be charged to any such reimbursing employer in the same proportion as the wages from such reimbursing employers bears to the total amount of all wages in the individual's base period. Any benefits not charged to a reimbursing employer shall be charged to the most recent employer or as otherwise required by RSA 282-A.