Assignment Sale Taxes in Ontario: HST and the Flipping Rule, Explained for 2026

Thousands of pre-construction buyers across Markham and the GTA are facing 2026 closings they no longer want, and many discover the tax rules only after they have priced their assignment. That order is backwards. The taxes decide your real exit number, so they come first.

Here are the two rules that matter, in plain language.

Rule One: HST Applies to Every Assignment

Before May 2022, HST on assignments depended on the original buyer's intentions. That test is gone. Every assignment sale of a newly built home in Ontario is now a taxable supply, whether you bought to live there, to rent, or to flip.

The detail that saves assignors money sits in the paperwork. When the assignment agreement states in writing that part of the price reimburses the deposits you already paid to the builder, HST applies only to the amount above the deposit, not the full assignment price. Skip that wording and the tax math gets ugly. The Canada Revenue Agency explains the treatment in its guidance on assignments of purchase and sale agreements.

Rule Two: The Flipping Rule Can Make Your Profit Business Income

Since January 1, 2023, Canada's residential property flipping rule has applied to assignment sales. If you held the rights to the property for less than 12 months before assigning, any profit is automatically deemed business income. That means 100 per cent taxable at your marginal rate, with no capital gains treatment and no principal residence exemption.

There are limited life event exceptions, including death, separation, serious illness or disability, job loss, and qualifying relocation. Beyond 12 months, the automatic rule falls away, but CRA can still treat assignment profits as business income based on the facts of your situation. The rule is set out in CRA's own income tax guidance.

Losses follow their own rules, and in 2026 many assignors are selling below their original price. That changes the tax picture again, which is exactly why the accountant runs the numbers before the price is set.

The 2026 Reality: Many Assignments Are About Capping a Loss

A record wave of GTA pre-construction units is completing into a softer condo market, and lenders finance the appraised value, not the contract price. For buyers who signed at the peak, the honest comparison is not loss versus no loss. It is a capped, controlled loss through an assignment versus an uncontrolled one through default, where the builder keeps the deposits and can sue for the resale shortfall on top. Ontario courts have already ordered defaulting buyers to pay exactly that.

A planned assignment, priced to today's market with the taxes understood in advance, closes the file on your terms. The full playbook, from builder consent to marketing restrictions to timing, is here: Selling a Pre-Construction Assignment in Markham.

Price After Tax, Not Before

The sequence that protects Markham assignors is simple:

1. Your lawyer reads the agreement of purchase and sale for consent rules and fees.
2. Your accountant models HST and income tax on realistic sale prices.
3. The assignment is priced and marketed from the net number — the one you actually keep.

Do it in that order and there are no surprises at the finish line. Do it in reverse and the surprise arrives with the tax return.

Frequently Asked Questions