Not necessarily. Substantiality is proportional to the cost of establishing the business, so a modest but complete investment in an asset-light brokerage can qualify. The harder test is showing the enterprise will be more than marginal.
Small can be substantial; marginal is the real risk
Hypothetical example: the owner plans to open the U.S. brokerage with an office lease, software, the federal bond and a carrier-payment float that together cost a fraction of what a trucking company or a retail store would. If those items are what the business genuinely needs, funding all of them satisfies proportionality. The officer will then ask whether the business will employ anyone but the owner. The plan should show a dispatcher hired in the first months and a sales representative within the first year, supported by the Canadian brokerage's revenue history and by shipper letters of intent, so the projections are believable. The owner's Canadian citizenship establishes treaty nationality, sole ownership establishes direction, and funds traced from savings or from dividends declared by the Canadian company establish source. What would not work is an investment consisting mainly of a laptop and a home office, or projections showing the business paying only the owner's salary for years.
Hypothetical example: a Canadian owner plans a U.S. custom-orthotics workshop and has signed equipment orders that can be cancelled without cost if the visa is refused. Those orders do not yet show an irrevocable commitment. The first review should trace the funds, test personal control of the enterprise, and compare committed spending with what this particular workshop genuinely needs. The money must be at risk, and the business plan must show a real operation that will not be marginal. A refundable intention to buy is usually the point that needs to change before filing.