What it means
Mortgage originators hedge their pipelines in the to-be-announced (TBA) market. An originator selling an MBS forward locks a price for loans still on its books, shedding much of the interest rate risk.
But the forward eventually demands delivery of a pooled security, and building that pool is not always the cheapest path. Assignment of trade is the shortcut.
The originator assigns its TBA obligation to a third-party investor, who agrees to buy the underlying whole loans immediately, collect their income streams, and deliver the MBS into the original trade. The originator unwinds its hedge, the investor gets the loans, and the dealer receives the security it was promised.
The pricing flows through the hedge. The price at which the whole loans transfer to the assignee is set by the price of the TBA trade being assigned, so the originator's hedge price becomes the sale price of its loans.
Executed well, the structure saves fees, buybacks and transfer costs. Risk rearranges rather than vanishes.
The assignee takes default risk on the loans it buys, the dealer holds the MBS with its prepayment risk, and the originator frees balance sheet capacity to write new loans. Actual AOT agreements are filed as material contracts, and one appears in the SEC's EDGAR archive as a 2002 exhibit.
The process draws criticism for its plumbing. Assignments run on stacks of paperwork and email chains, and industry participants have pushed for standardised electronic platforms so trade data is tracked and archived cleanly.
The TBA market's scale makes the plumbing matter, since very large volumes of mortgage risk move through these forward trades every month, so even small error rates translate into real money and real disputes. For a manager near mortgage finance, AOT is a reminder that hedges create their own logistics.
The cheapest hedge is not always the cheapest to settle, and the assignment mechanism exists to close that gap. That is why the call for a single electronic assignment platform keeps returning.
In practice
Real-world examples.
Example
An originator with $30 million in locked loans assigns its TBA trade to an investor, avoiding pool delivery costs and freeing warehouse line capacity.
Example
An investor takes assignment of a trade, collects loan payments for two months, and delivers the MBS into the dealer's forward contract at settlement.
Example
A dealer receives its promised security from the assignee rather than the originator, and the original hedge closes without a buyback.
Formula
Calculation
The economics chain through three prices. The originator sells the MBS forward at the TBA price, the assignee buys the whole loans at a price derived from that same trade price, and then delivers the pooled security into the TBA trade at settlement. The originator's net equals the TBA price minus loan funding costs, with delivery costs avoided through the assignment.
Worked example. An originator has $30,000,000 of locked loans hedged at a TBA price of 101.00 (per 100 of face value) and funded at a cost of 99.50.
- Proceeds at the TBA-implied price: $30,000,000 x 1.01 = $30,300,000
- Funding cost: $30,000,000 x 0.995 = $29,850,000
- Gross gain: $30,300,000 - $29,850,000 = $450,000
- If delivering through its own pool would have cost 0.10 points ($30,000 on $30,000,000), the gain by that route would be $420,000, so the assignment saves $30,000. The figures are illustrative.Case study
Seen in the real world.
This fictional case study shows the unwind. Fictional lender Harborpoint Mortgage sells $50 million of MBS forward to hedge its spring pipeline. Rather than pooling loans itself, it assigns the trade to fictional aggregator Keystone Capital, which buys the loans at the TBA-implied price and delivers the security.
Harborpoint books its hedge gain and starts a new pipeline the same week. In this illustrative story, the two firms confirm the assigned trade details by reference number, trade date and settlement date before any money moves. A mismatch in one field delays settlement by a day, which is why Harborpoint's operations team checks every assignment against the dealer's confirmation.
Watch out
Common mistakes.
- Treating the assignment as risk removal. It rearranges default, prepayment, and rate risk among the three parties rather than eliminating any of them.
- Running AOT on manual paperwork without controls. The process is document-heavy and error-prone, which is why the industry pushes for standardised electronic platforms.
- Mispricing the whole-loan leg. The loan sale price derives from the assigned trade's price, so a stale or misread TBA quote propagates into the loan price.
Questions
People also ask.
What is assignment of trade?
A three-party arrangement in the MBS to-be-announced market. The originator assigns its forward delivery obligation to a third party, which buys the underlying loans and delivers the pooled security to the dealer.
Why do mortgage originators use AOT?
To unwind their TBA hedges cost-effectively. The originator sells the loans and transfers the delivery duty in one step, saving pooling, transfer, and buyback expenses while freeing capacity to write new loans. The price of the assigned trade becomes the price of the loans.
What is the main criticism of AOT?
Its plumbing. Transactions rely on manual paperwork and email, making errors and missed information common, and industry figures have called for a single standardised electronic platform. The 2002 AOT agreement on the SEC's EDGAR system shows how document-heavy the process has always been.
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