"Business income" is defined in Section 7-4-2 NMSA 1978 and Part 3.5.1 NMAC. The business income to be apportioned is net business income after taking into account only those expenses and deductions which are allowable under the United States Internal Revenue Code of 1986, as amended, which are related to the production of business income. Expenses and deductions attributable to nonbusiness income may not be taken into account in arriving at net business income to be apportioned.
N.M. Admin. Code § 3.5.10.9