No. A branch, an affiliate or a parent all satisfy the qualifying relationship as readily as a subsidiary. What the relationship must be is real, documented, and accompanied by evidence that both the Canadian and the United States operations are actively doing business.
The relationship can take four shapes; only the evidence differs
Companies often incorporate a United States subsidiary purely because they have been told L-1 requires one, which adds cost and a corporate structure they did not want. The statute is broader than that. What matters is that the entity abroad and the entity in the United States stand in one of the recognised relationships and that both are doing business as employers throughout the stay. For a subsidiary the proof is ownership: share registers, incorporation documents, and evidence of control. For a branch the proof is that the same legal person is registered and operating in the United States, which is shown through state registration, tax accounts, premises and trading records. Choose the structure for commercial and tax reasons, then build the evidence the chosen structure requires, rather than the other way around.
Hypothetical example: a commercial-greenhouse director will oversee a related American operation. The review should decide whether the role is primarily managerial or executive, using share records, registrations, payroll, reporting lines, and decision authority. Ask for the missing primary record before selecting a filing or travel step. The usual error is that a senior title fails if evidence shows mostly ordinary production work. Put the conclusion in a dated fact sheet so later changes in duties, ownership, or qualification remain visible.