Its formation certificate, share ledger, lease, recent tax filings, payroll registers, sales records and supplier or customer contracts. The parent's ownership must appear on the ledger, and both entities must be shown to be doing business, not merely registered.
Assembling the subsidiary's file
Start with the ledger entry recording the Québec company's ownership and the bank record of the original capital contribution, then the certificate of formation and the operating agreement or bylaws. Add the U.S. lease for the warehouse and office, the last two years of federal and state tax filings, quarterly payroll returns showing the three employees, and a sales ledger or a set of invoices demonstrating trading activity.
Include the departing general manager's resignation letter and the current organization chart, because the vacancy is the reason for the transfer and a reviewer should see it. For the parent, provide its Québec financial statements, headcount by department and a description of the back-office services it provides to the subsidiary, since that supports the argument that his U.S. week is managerial.
Finally, three years of payroll under the parent's legal name for the manager himself. None of these is exotic; the failure mode is sending the narrative without them.