There is no set figure. Substantiality is proportional to the total cost of acquiring the enterprise, so a business with land and buildings requires a correspondingly large commitment, and only capital genuinely at risk counts toward it. Filing and visa charges are separate and published officially.
The proportion is what is measured, not the headline price
Applicants often ask for a threshold and are frustrated to learn there is not one. The comparison is between what has been invested and what the enterprise costs to buy or to establish, and the proportion expected rises as the total falls: a modest service business may need close to its whole cost committed, while a larger acquisition can meet the test at a lower percentage. For the Kavanaghs the headline price is misleading in both directions.
Any portion financed by a loan secured on the resort drops out of the numerator entirely. Meanwhile the denominator is larger than the purchase price alone, because it includes what is genuinely required to make the enterprise operational: dock repairs, licences, insurance, initial payroll, working capital for the pre-season months when nothing is earned. Government charges for the application itself are set out officially and are trivial beside these numbers, but the fee schedule remains the only reliable source for them.