A participating province is a province which charges HST.
Under the current self-assessment rules, if you purchase goods or services in a non-participating province (one in which only GST is charged), but you use, consume or supply them within a participating province, you are required to self-assess the provincial portion of the HST. This does not apply if you would be getting an input tax credit for the GST/HST.
Due to the fact that the provincial component of the HST varies between provinces, the self-assessment rules are being expanded. Generally, the existing exemptions from the requirement to self-assess would continue under the new rules.
Under the new rules, if the amount of tax to be self-assessed is less than $25 in a calendar month, there is no requirement to self-assess.
The expanded self-assessment rule also applies if goods are purchased in a participating province, and are then brought into another participating province where the provincial component of the HST is higher. The amount of tax to be self-assessed would be calculated by taking the difference in the provincial components, and multiplying by the lesser of
Example: A New Brunswick resident purchases a wedding dress in Ontario for $3,000, paying 13% HST, or $390. New Brunswick's HST rate is 15%. On return to New Brunswick, the New Brunswick resident would be required to self-assess tax on the $3,000 at the rate of 2% x $3,000, or $60.
The expanded self-assessment rule for services and intangible personal property (IPP) would also apply when IPP or a service is acquired in a province for consumption, use or supply "significantly" (generally, 10% or more) in participating provinces for which the provincial component of the HST is higher than in the province of acquisition.
The rules on self-assessment can be found in the Canada Revenue Agency GST/HST Technical Information Bulletin B-079, Self-Assessment of the HST on Supplies Brought Into a Participating Province.