Minn. Stat. § 518A.30: INCOME FROM SELF-EMPLOYMENT OR OPERATION OF A BUSINESS.

For purposes of section 518A.29, income from self-employment or operation of a business, including joint ownership of a partnership or closely held corporation, is defined as gross receipts minus costs of goods sold minus ordinary and necessary expenses required for self-employment or business operation. Specifically excluded from ordinary and necessary expenses are amounts allowable by the Internal Revenue Service for the accelerated component of depreciation expenses, investment tax credits, or any other business expenses determined by the court to be inappropriate or excessive for determining gross income for purposes of calculating child support. The person seeking to deduct an expense, including depreciation, has the burden of proving, if challenged, that the expense is ordinary and necessary.