Mich. Comp. Laws § 206.621: Nexus; "actively solicits" and "physical presence" defined.

Sec. 621.

(1) Except as otherwise provided in this part, a taxpayer has substantial nexus in this state and is subject to the tax imposed under this part if the taxpayer has a physical presence in this state for a period of more than 1 day during the tax year, if the taxpayer actively solicits sales in this state and has gross receipts of $350,000.00 or more sourced to this state, or if the taxpayer has an ownership interest or a beneficial interest in a flow-through entity, directly, or indirectly through 1 or more other flow-through entities, that has substantial nexus in this state.

(2) As used in this section:

(a) "Actively solicits" means either of the following:

( i ) Speech, conduct, or activity that is purposefully directed at or intended to reach persons within this state and that explicitly or implicitly invites an order for a purchase or sale.

( ii ) Speech, conduct, or activity that is purposefully directed at or intended to reach persons within this state that neither explicitly nor implicitly invites an order for a purchase or sale, but is entirely ancillary to requests for an order for a purchase or sale.

(b) "Physical presence" means any activity conducted by the taxpayer or on behalf of the taxpayer by the taxpayer's employee, agent, or independent contractor acting in a representative capacity. Physical presence does not include the activities of professionals providing services in a professional capacity or other service providers if the activity is not significantly associated with the taxpayer's ability to establish and maintain a market in this state.