Subject to prior sale: why the part is gone when your PO arrives, how long a quote lives, and how to hold it

The short version

• "Subject to prior sale" means the quote is not a reservation. The seller is telling you the price and availability were true when written, and may not be true when you act on them.
• A stated validity period (say, "valid 15 days") is not, by itself, a promise to hold the part. Under US commercial law an offer can generally be withdrawn before it is accepted; the UCC's "firm offer" exception has specific conditions. When a quote carries both a validity period and "subject to prior sale," ask the seller which one governs.
• Treat the deal as made when the seller confirms your purchase order — not the moment you read the quote.
• The fastest way to hold a part is to ask, in writing, before you commit it to your own customer — not to assume the quote already did that for you.

"Subject to prior sale" and "unsold": what the clause is telling you

A quote line that says stock, or shows a lead time of zero days, tells you the seller believes the unit is on a shelf and ready to move. It does not tell you that the unit has been set aside for you. "Subject to prior sale" (sometimes "offer subject to prior sale," "unsold," or just implied by the seller's standard terms) is how a seller says the same thing plainly: the price and the availability shown are good as of the moment the quote was written, and the unit can be sold to whoever's purchase order lands first.

In practice, that qualifier is often written once — in the seller's standard terms at the top or bottom of the quote, or in the body of the covering email — and applies to the whole document, not restated against each part number. A long multi-line quote with no such wording on any individual row can still carry it as a blanket condition you only see once.

This is not a trick. A single serial number can only go to one buyer, and a seller that has quoted a part is not thereby holding it off the market. Whether your own customer needs "STK" to mean something firmer than that is a question for your own quote to them, not a fact the supplier's wording changes.

What a stated validity period binds — and what it doesn't

The sale of goods in the United States is mostly governed by Article 2 of the Uniform Commercial Code (UCC), a model law adopted, with local variations, by state legislatures. Two of its rules explain why a validity period on a quote is not the same as a promise it will be honored.

First, the general rule: an offer can generally be withdrawn before it is accepted, unless the parties have created an enforceable option contract. Whether a particular quote is an offer at all, or an invitation for you to make one with your purchase order, depends on its wording and the circumstances; either way, the starting point is that the seller can change its mind until there is an acceptance.

Second, the exception: UCC § 2-205 describes a merchant's "firm offer." The statute's own words: "An offer by a merchant to buy or sell goods in a signed writing which by its terms gives assurance that it will be held open is not revocable, for lack of consideration, during the time stated or if no time is stated for a reasonable time, but in no event may such period of irrevocability exceed three months; but any such term of assurance on a form supplied by the offeree must be separately signed by the offeror." A "merchant" is defined in § 2-104(1), in part, as a person who deals in goods of the kind or otherwise by occupation holds itself out as having knowledge or skill peculiar to the practices or goods involved.

For a buyer, the practical point is narrower than a legal answer. The statute speaks of a signed writing that gives assurance it will be held open; a quote that states a number of days and also says "subject to prior sale" tells you, in its own words, that the unit may go to someone else in the meantime. Whether any particular quote is a firm offer depends on its exact wording and the applicable state law — this guide cannot answer that. The step that works either way: when a quote carries both a validity period and a prior-sale qualifier, ask the seller in writing which one governs, rather than assume the number of days does.

This is general information, not legal advice. Wording, state law and a given seller's own terms and conditions can change the answer; if a dispute over a quote matters, ask a lawyer. When money is on the line, get the seller's confirmation in writing rather than relying on how a quote reads.

Offer, acceptance, and when a deal is actually made

UCC § 2-206 speaks of "an order or other offer to buy goods" — a purchase order is itself an offer to buy. Unless the language or circumstances unambiguously indicate otherwise, an order for "prompt or current shipment" is construed as inviting the seller to accept either by a prompt promise to ship or by prompt or current shipment. Under § 2-204, a contract for the sale of goods may be made in any manner sufficient to show agreement, including conduct by both parties, even if the moment of its making is undetermined. For a buyer, the useful point is that both sections look at what the seller does in response to your order: a promise to ship, a shipment, or other conduct showing agreement.

The practical version: your PO tells the seller what you want to buy, at the price and terms you saw on the quote. Until the seller responds — confirming the line, the price, the quantity and that the unit is still available — treat nothing as locked on their side, whatever the quote implied. Ask for that confirmation in writing before you tell your own customer the part is covered.

In our own client portal, RFQ Radar, that step is visible: you put quoted lines on a purchase order, set the quantity and leave a note; our reply to the order comes back in the portal, and you accept it or tell us what does not work. The order is kept as a PDF, with the lead time of every line.

Why "in stock" moves

A few ordinary reasons explain why a line that read "stock" yesterday can read "sold" today, none of them requiring bad faith on the seller's part:

• One physical unit, more than one inquiry. The same part number can be quoted to several buyers in the same week; only one purchase order gets there first.
• A quote isn't necessarily a reservation in the seller's own system. Unless the seller tells you otherwise, assume a unit is committed only once an order is entered against it, not when a quote is answered.
• A PO in hand is firmer than an open inquiry. If another buyer's order lands while your quote is still just a quote, the seller has something firmer to act on than your intent to order.
• Urgent buyers move first. A buyer with an aircraft on ground who confirms and orders fast can get there before one still comparing offers.

None of this is specific to any one seller or marketplace; it follows from what a quote is — an answer to a question, not a hold on an asset.

Practical ways to ask a seller to hold a part

These are things to ask the seller for, not something a quote gives you automatically. Different sellers will answer differently, and some will decline; the point is to ask before you rely on the answer, not after.

• Send the PO fast. The single biggest lever you control is how quickly your purchase order, referencing the quote number and date, reaches the seller after you decide to buy.
• Ask for a written order acknowledgement. Not just an email receipt — a confirmation that names the part, quantity, price and that the specific unit is now reserved against your order, before you pass that assurance on to your own customer.
• Ask about a deposit or a hold request. Some sellers will hold a unit for a stated time against a deposit or partial payment; others will not. If one offers it, get the length of the hold, whether it is refundable, and the exact terms in writing before you send money.
• Confirm by phone on anything urgent. A short call to check the unit is still available, before you re-quote your own customer, costs less than a quote that turns out to be stale.

What to write on the RFQ and the PO

On the RFQ

1. Ask how long the quote is valid, and whether it is subject to prior sale.
2. Ask whether the quoted unit is on the seller's own shelf now, or still to be sourced — "stock" alone doesn't say whose shelf. (See our guide to aircraft parts lead time for the rest of what "stock," "ARO" and "TBA" usually mean.)
3. Ask whether the seller will hold the unit against a signed PO, against a deposit, or not at all.

On the PO

1. Reference the exact quote number and date you are ordering against.
2. Ask for a written order acknowledgement confirming the line, quantity, price and availability before you rely on it.
3. If your own customer is waiting on an answer, say so — a seller who knows there is a deadline on your end can tell you sooner if the part is already gone.

What to ask when the quote says stock

For the rest of what makes two quotes for the same part comparable — condition, certificates, minimum order, ships-from country — see our guide to comparing quotes from several suppliers and how to read an aircraft parts quote.

Sources

• UCC § 2-204, Formation in General — Legal Information Institute, Cornell Law School.
• UCC § 2-205, Firm Offers — Legal Information Institute, Cornell Law School.
• UCC § 2-206, Offer and Acceptance in Formation of Contract — Legal Information Institute, Cornell Law School.
• UCC § 2-104(1), definition of "merchant" — Legal Information Institute, Cornell Law School.
• Offer — Wex, Legal Information Institute, Cornell Law School.
• Firm offer — Wex, Legal Information Institute, Cornell Law School.