The Assignment Deal That Almost Cost an Extra $23,000 in HST

The situation

Imran, a pharmacist, had spent the better part of a year working through a separation. The matrimonial home was sold, the proceeds divided under a separation agreement, and by early spring Imran was ready to buy a new home — somewhere with enough room for the children on the weeks they stayed, close enough to work, and, ideally, not another decade-old resale house needing repairs. A real estate agent flagged a listing that was a little different from the usual: a pre-construction detached home in Caledon, not sold directly by the builder, but being assigned by the person who had originally signed the purchase agreement two years earlier.

An assignment sale happens when the original buyer of a pre-construction home — the person who signed with the builder before the house was even framed — sells their contract rights to someone else before the building is finished and the deal closes. The new buyer steps into the original buyer's shoes: same builder, same house, same closing date, but a new purchaser on the paperwork. The seller in this kind of deal, sometimes called the assignor, is not selling a house; they are selling the right to buy one.

The assignor here was Kwame, who had put a deposit down on the home as an investment, never intending to live in it, and now wanted out before the building finished and a mortgage came due. Imran's agent negotiated a price for the assignment itself — on top of what Kwame still owed the builder — and within a couple of weeks an assignment agreement of purchase and sale landed in Imran's inbox, ready to sign. Imran sent it to Treadstone Law for review before signing, the way a title search and mortgage commitment get checked before a resale deal closes.

What the review found

The math in the agreement looked straightforward at first glance. Kwame's original contract price with the builder was roughly $790,000. Imran agreed to pay Kwame an assignment fee of $180,000 for the right to take over that contract — the premium reflecting how much the pre-construction market had moved since Kwame signed. Total cost to Imran, all in: about $970,000, comfortably inside what the mortgage pre-approval supported.

The problem was one clause, easy to read past: the assignment fee was listed as "$180,000 plus applicable taxes." Imran had read that as boilerplate — the kind of phrase that shows up on every legal document and rarely means anything is actually owed. It meant something here.

Since 2022, the sale of an assignment on a newly built home has been treated as a fully taxable transaction for GST/HST purposes in its own right, separate from the HST that applies to the underlying purchase from the builder. That builder-level HST is usually folded into the advertised price and offset by a new housing rebate when the buyer intends to live in the home. The assignment fee is a different transaction entirely — money changing hands between two private individuals, Kwame and Imran, for the value of a contract — and HST applies to the full assignment fee, not just to Kwame's profit on the deal.

At 13 percent, HST on a $180,000 assignment fee comes to about $23,400. The agreement's wording made Imran, as the buyer, responsible for that amount on top of the $180,000, due at closing along with everything else. Imran's budget had no room for an extra $23,400 that hadn't been part of any conversation with the agent or with Kwame. Had the agreement been signed as drafted and the point only surfaced when the closing statement arrived from the lawyer handling that stage, Imran would have been choosing between finding $23,400 on short notice or risking the deal falling apart days before closing — neither a fair position for a single parent who had already been through a difficult year.

There was a second wrinkle worth flagging at the same time. Because Kwame had never lived in the home and always intended it as an investment, Kwame was not entitled to claim the new housing rebate that reduces the HST embedded in the builder's price. Imran, buying as a genuine principal residence, likely would be entitled to that rebate — but only if the paperwork properly assigned that entitlement and Imran's intention to occupy the home was documented correctly in the assignment agreement itself. As drafted, the agreement was silent on this too, leaving open the risk that the rebate could be missed or contested at the builder's final closing.

What we did

1. Explained the tax exposure in plain terms before advising on next steps. Rather than simply flagging the clause as a risk, we walked Imran through why HST applies to an assignment fee at all, what the $23,400 figure represented, and why it was separate from the HST already built into the price Kwame owed the builder. Understanding the mechanics made the negotiating position clearer.
2. Went back to the agent and Kwame's side before signing, not after. Because the review happened before Imran signed anything, there was still room to negotiate. We proposed amending the price term so the $180,000 assignment fee was inclusive of HST, meaning Kwame's net proceeds would absorb the tax rather than Imran paying it on top.
3. Added a clause addressing the new housing rebate directly. The revised agreement confirmed Imran's intention to occupy the home as a principal residence and included Kwame's cooperation in assigning rebate entitlement, so the builder's closing paperwork would reflect Imran as the party claiming it rather than leaving the point unresolved.
4. Set out the full closing costs in writing for Imran's own records. Beyond the assignment fee itself, we itemized the land transfer tax, the builder's own closing adjustments, and the legal costs of the eventual closing, so there was one clear number to plan a mortgage and down payment around — not a moving target.

The outcome

Kwame's side agreed to the revised terms. Kwame had already priced in a profit on the assignment and, after some back-and-forth, accepted that the $180,000 figure would be treated as inclusive of HST rather than an additional charge — effectively reducing Kwame's net proceeds by about $20,700 once the tax was backed out of the total, but keeping the deal moving without a renegotiation fight closer to closing, when Kwame's own leverage would have been weaker. The rebate assignment clause went in without objection, since it cost Kwame nothing and made the paperwork cleaner for everyone, including the builder's closing team.

Imran signed the amended assignment agreement roughly two weeks after the original draft first arrived. The $23,400 that would otherwise have appeared as a surprise on a closing statement months later never became Imran's problem to solve on short notice. The home closed on schedule the following autumn, with the builder's own closing handled by the same file and the rebate properly credited toward the purchase price rather than needing to be claimed separately after the fact.

Nothing dramatic happened here — no missed deadline, no last-minute scramble, no court application. That is exactly the point. The gap in the agreement was real and the number attached to it was significant relative to Imran's budget, but it was caught at the one point in the transaction where it could still be fixed cheaply: before a signature went on the page.

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