Premium is based on your loan-to-value (LTV). We add 0.20% if you choose a 30-year amortization (available to first-time buyers or new builds). If your down payment is non-traditional and your LTV is in the 90.01–95% band, CMHC charges 4.50% instead of 4.00%. Ontario charges 8% PST on the premium; this tax is paid in cash at closing and is not added to your mortgage.