Michigan Schedule of Apportionment MI-1040H is not only used for businesses with assets or employees. There is also a Sales Factor under Part 2: Computation Of Income Attributable To Other State(s), Line 16 that states "Business income included in adjusted gross income that is subject to apportionment (include ordinary and portfolio income, and all other business income)." 

Sales Factor

Divide the total sales in Michigan during the tax year by the total sales everywhere during the tax year.

"Sales" includes gross receipts from sales of tangible property, rental of property, and providing of services that constitute business activity. Exclude all receipts of nonbusiness income.

1. From within your TaxACT return (Online or Desktop) click on the State Q&A tab and then click Michigan directly below the blue tabs
2. Click Subtractions to expand the category, then click Schedule NR for nonresidents and part-year residents
3. Continue to the screen titled Michigan – Schedule NR – Form 1040H and click Yes to allocate the business income to other states using the sales factor
4. Click Review to the right of the form you want to review or click on Add to create a new form
5. The program will proceed with the interview questions for you to enter or review the appropriate information
6. Once you reach the screen titled Michigan – Business income, you can enter the business income included in adjusted gross income that is subject to apportionment

Once you have completed this section of the Q&A, the correct amounts will be reflected on Line 7 of Michigan Schedule NR.