When a supplier demands a 25% price increase mid-production, substitutes materials without approval, or refuses to honor the original quotation, your legal position depends on what you signed -- and what you didn't.
You negotiate a price, issue a purchase order, wire a deposit, and confirm a delivery date. Two weeks later, your supplier sends a WeChat message: "Raw materials increased 30%, new price USD 2.85/unit" -- up from the agreed USD 2.20. Or you receive the pre-shipment photos and notice the zipper is a different brand than the one specified. Or your supplier simply ships 60% of the ordered quantity, explaining they had to "allocate to another customer." Every foreign buyer sourcing from China will encounter some version of the unilateral contract change.
The legal answer is straightforward: under the CISG and Chinese contract law, a party cannot unilaterally modify a concluded contract. But the practical answer is more complex. Your deposit is with the supplier. Your retail launch date is approaching. Your customers are waiting. And the supplier knows all of this. The supplier's calculation is simple: the cost to you of walking away -- lost deposit, lost time, lost sales -- exceeds the cost of accepting the change. You are not negotiating; you are being extorted by leverage.
This page provides a comprehensive analysis of unilateral contract changes by Chinese suppliers, covering common scenarios, the legal framework governing contract formation and modification, the critical distinction between purchase orders and framework contracts, price fluctuation clauses, material substitution controls, and practical response strategies when a supplier attempts to change the deal.
The most common form of unilateral change. The supplier has accepted your PO, received your deposit (typically 30%), and begun production. Then they demand a price increase -- citing increased raw material costs, RMB appreciation against the dollar, higher labor costs, or "market conditions." The demand often arrives after the deposit is non-refundable and the buyer has committed to downstream customers at a fixed price. The supplier may halt production until the new price is accepted.
The supplier substitutes specified materials or components for cheaper alternatives: "brand-name" zippers become generic ones, specified-grade stainless steel becomes lower-grade, approved fabric becomes a cheaper blend, or branded electronic components become unbranded equivalents. The supplier often argues the substitution is "equivalent quality" or "industry standard" and may not even inform the buyer until after shipment -- when the substitution is discovered during quality inspection at the destination.
The supplier makes changes to the agreed product specifications or design without consultation: altering dimensions, changing color formulations, modifying packaging design, or "simplifying" features to reduce manufacturing cost. The supplier may claim the change was "necessary for production" or that it "improves the product." In reality, the supplier is reducing cost and hoping the buyer either does not notice or cannot afford to reject the shipment.
The supplier's sales representative quotes attractive terms to secure the order, then the factory manager or owner refuses to honor them after the PO is issued. Common variations: the quoted EXW price is recast as FOB (passing freight costs to buyer); the quoted lead time is extended by 30-45 days; MOQ increases from the quoted 500 units to 2,000; or "optional" tooling costs become "required" after the order is placed. The supplier's justification is typically that the sales rep made a mistake or that the buyer "misunderstood" the quotation.
The supplier produces less than the ordered quantity and allocates the shortfall to a different customer -- often one paying a higher price or one with a longer relationship. The buyer receives a partial shipment with a promise that "the rest will follow" -- which it never does, or arrives months later when the selling season has ended. The supplier may claim production capacity constraints, raw material shortages, or quality issues with the batch -- but the real reason is a better commercial opportunity elsewhere.
After the PO is accepted, the supplier demands revised payment terms: the 30% deposit becomes 50% or 70%; the balance payment demanded before shipment instead of after; or previously agreed T/T terms are switched to irrevocable L/C at sight (shifting the cost and complexity of L/C issuance to the buyer). The timing is critical -- the demand often comes after the buyer has already arranged financing, budgeting, and downstream commitments based on the original payment structure.
The supplier asserts that a WeChat conversation, a phone call, or an in-person meeting constituted a binding modification to the written contract. "Your Mr. Smith agreed to the new price at the Canton Fair" -- even though no follow-up written confirmation was issued. Under CISG Article 29, oral modifications are generally permissible unless the contract contains a No Oral Modification (NOM) clause. Chinese courts have been inconsistent in their treatment of NOM clauses, making this a genuinely contested area.
The CISG governs contract formation for most international sale-of-goods contracts involving Chinese suppliers. Under Article 14, a proposal is an offer if it is "sufficiently definite" (indicating the goods and expressly or implicitly fixing or making provision for determining the quantity and price) and indicates the offeror's intention to be bound in case of acceptance. Under Article 18, acceptance may be by statement or other conduct indicating assent. Under Article 23, a contract is concluded when acceptance becomes effective. This means that an exchange of PO and sales confirmation -- even via email or WeChat -- can form a binding contract if the communications are sufficiently definite and indicate an intention to be bound.
Article 29(1) provides that a contract may be modified by the mere agreement of the parties. Article 29(2) provides that a contract in writing that contains a clause requiring any modification to be in writing may not be otherwise modified -- however, a party may be precluded by its conduct from asserting such a clause to the extent that the other party has relied on that conduct. This is the "No Oral Modification" (NOM) clause provision. Critically, a buyer's conduct in response to an oral modification -- such as continuing to make payments at the modified price, accepting partial deliveries at modified terms, or remaining silent for an unreasonable period -- may constitute a waiver of the NOM clause, even if the buyer never expressly agreed in writing. This is why prompt, written objection to any attempted unilateral change is essential.
Under the Chinese Civil Code (effective January 1, 2021, replacing the Contract Law), Article 471 provides that parties may conclude contracts through offer and acceptance or other means. Article 472 defines an offer as an expression of intent to conclude a contract with another person that is specific and definite (indicating that the offeror is to be bound upon acceptance). Article 479 provides that acceptance is an expression of intent by the offeree to assent to the offer. Article 483: a contract is formed upon effectiveness of the acceptance, unless otherwise provided by law or agreed by the parties. Article 543: parties may modify a contract upon consensus through consultation.
A classic problem in China sourcing: the buyer issues a PO with detailed terms, the supplier responds with its own sales confirmation containing different (often supplier-favorable) terms, and the parties proceed to performance without resolving which document governs. Under CISG Article 19, a reply that purports to be an acceptance but contains additions, limitations, or modifications is a rejection and counter-offer -- unless the additions do not materially alter the terms. The supplier's sales confirmation typically does materially alter the terms (price, payment, liability, dispute resolution). However, if the buyer then pays the deposit and the supplier begins production without further discussion, both parties are performing under an ambiguous contract whose precise terms may be disputed. Chinese courts resolving battle-of-forms disputes often look to which party sent the "last shot" before performance began, or import terms from the CISG and the Chinese Civil Code as gap-fillers -- an unpredictable outcome that favors the party with local litigation experience.
Chinese courts and tribunals routinely find binding contracts formed through electronic communications. A WeChat exchange where the buyer says "Confirm order: 10,000 units, USD 2.20/unit, FOB Ningbo, delivery by June 30" and the supplier replies "Confirmed" can create a binding contract. The combination of a PO listing product, quantity, price, delivery date, and payment terms, followed by the supplier's written acknowledgment (even a brief "PO received, will arrange production"), satisfies the CISG Article 14 "sufficiently definite" standard. The key legal question in disputes is not whether a contract exists, but what its terms are -- and whether those terms include protections against unilateral changes.
Key Legal Insight: A supplier's demand for new terms is not itself a breach -- it is a proposed modification. The breach occurs when the supplier refuses to perform under the original contract terms. Your written response should (a) reject the proposed modification, (b) demand performance under the original contract terms, (c) reserve all rights including the right to claim damages, and (d) set a reasonable deadline for confirmation of continued performance. This response preserves your legal position and prevents the supplier from later claiming you acquiesced by silence.
The most consequential structural decision in China sourcing is whether to trade on a purchase-order basis or under a framework supply agreement. Many foreign buyers default to POs because they are quick, familiar, and the supplier is willing. This is a mistake. Here is why:
A standard purchase order is a single-transaction document. It specifies product, quantity, price, and delivery date for one order. It rarely contains robust provisions for: quality standards beyond "as per sample"; inspection and testing protocols; IP ownership and mold return; liquidated damages for delay or non-performance; material substitution approval requirements; price adjustment mechanisms or fixed-price guarantees; change order procedures; dispute resolution clauses specifying institution, seat, and governing law; or post-termination rights and obligations. When a supplier demands a price increase mid-production and the buyer's only contractual document is a one-page PO, the buyer's legal leverage is extremely limited. The supplier knows this.
A framework supply agreement ("Master Supply Agreement," "OEM Agreement," "Long-Term Purchase Agreement") establishes the legal infrastructure for an ongoing sourcing relationship. Key provisions include:
The framework agreement should contain a hierarchy clause: the terms of the framework agreement govern all transactions between the parties, and any conflicting term in a PO, sales confirmation, or other transaction document is void unless expressly agreed in a written amendment to the framework agreement. Each PO should explicitly reference the framework agreement: "This Purchase Order is issued pursuant to and governed by the Master Supply Agreement between the parties dated [date]. In the event of any conflict, the Master Supply Agreement prevails." This prevents the supplier from using its own sales confirmation to undermine the framework agreement through the battle-of-forms dynamic.
In volatile commodity markets, a rigid fixed-price contract can become commercially unsustainable for the supplier, inviting breach. Conversely, an open-ended price adjustment clause invites abuse. The solution is an objective, verifiable price adjustment mechanism:
The contract identifies the key raw material(s) driving product cost (e.g., copper for wiring, cotton for textiles, ABS resin for plastic components, steel for hardware). It specifies a publicly available, independently published price index for each material (e.g., LME copper cash price, Cotlook A Index for cotton, Platts polymer price assessments, Mysteel steel price indices for the Chinese market). The base price in the contract is tied to a specified index value as of the contract date. If the index moves by more than a defined threshold (e.g., +/- 10%) during the contract period, the price adjusts according to a pre-agreed formula: Adjusted Price = Base Price + (Material Cost Share x Index Change x Pass-Through Percentage). The "Material Cost Share" is the agreed percentage of the product's cost attributable to the indexed raw material. The "Pass-Through Percentage" determines how much of the index change is passed to the buyer (typically 50-80%, reflecting that the supplier bears some raw material risk). This mechanism eliminates opportunistic renegotiation by grounding price adjustments in objective data.
For shorter-term contracts (up to 12 months), a fixed price with defined adjustment bands offers simplicity. Example: "The price is fixed and binding for all POs issued within 6 months of the Effective Date. Thereafter, either party may request a price review by providing 30 days' written notice with supporting documentation of changed cost factors. Any price adjustment must be mutually agreed in writing. If the parties cannot agree, the price remains unchanged." This gives the supplier a mechanism for legitimate price review while preventing unilateral imposition.
For contracts priced in USD but with RMB-denominated manufacturing costs, RMB appreciation against the dollar can erode the supplier's margin. The contract should specify: (a) the reference exchange rate (e.g., USD/CNY central parity rate published by the People's Bank of China as of the contract date); (b) a fluctuation band within which no adjustment is made (e.g., +/- 3%); and (c) a sharing mechanism for exchange rate movements beyond the band (e.g., 50/50 sharing of the impact on the supplier's RMB revenue). Without such a provision, a sharp RMB appreciation will trigger the same unilateral renegotiation dynamic as a raw material price spike.
Material substitution without approval is one of the most difficult disputes to prove post-shipment. The contract should establish a clear prohibition and control regime:
When a supplier attempts a unilateral change, your response depends on your commercial position, contractual leverage, and the value at stake. Here is a framework for decision-making:
| Factor | Favors Negotiation | Favors Termination |
|---|---|---|
| Contract Strength | PO only, no framework agreement, limited contractual protections | Robust framework agreement with fixed price, NOM clause, and clear breach remedies |
| Commercial Urgency | Imminent retail launch, committed to downstream customers, seasonal goods | Flexible timeline, alternative suppliers identified, buffer stock available |
| Deposit at Risk | Large deposit (30%+) with the supplier; limited ability to recover | Small deposit, or confidence in legal recovery through asset preservation |
| Supplier Alternatives | Highly customized product; limited or no alternative manufacturers | Commodity or easily replicable product; multiple qualified suppliers |
| Change Magnitude | Modest adjustment (5-10%); supplier has legitimate cost pressure | Large adjustment (25%+); change is opportunistic, not cost-justified |
| Supplier Relationship | Long-standing relationship, overall positive history, isolated incident | New or already strained relationship, pattern of non-performance |
If the supplier refuses to perform at the contract price, the buyer may purchase substitute goods (a "cover purchase") from an alternative supplier and claim the difference in cost as damages. Under CISG Article 75, if the contract is avoided and the buyer has made a cover purchase in a reasonable manner and within a reasonable time, the buyer may recover the difference between the contract price and the cover price, plus any further damages under Article 74. Key requirements: the cover purchase must be made within a reasonable time after avoidance; the goods must be reasonably comparable to the original contract goods; and the buyer should document efforts to obtain the best available price. The cover purchase sets a concrete damages figure that is often easier to prove than abstract market price differentials under Article 76.
The supplier's unilateral change demand is itself evidence of breach (anticipatory breach if the supplier states it will not perform at the contract price, or actual breach if the supplier ships non-conforming goods). Preserve: (a) the original contract, PO, and related communications establishing the agreed terms; (b) the supplier's communication demanding the change (WeChat, email, letter) -- screenshot or export immediately, and notarize for formal proceedings; (c) your written response rejecting the change, demanding performance, and reserving rights; (d) any subsequent communications regarding the dispute; (e) evidence of cover purchases made (POs to alternative suppliers, price quotes obtained); and (f) evidence of losses incurred (communications from your customers, shipping schedule disruptions, launch delays).
A formal legal demand letter (bilingual, on law firm letterhead) serves multiple functions: it communicates that the dispute has escalated from commercial negotiation to a legal matter; it creates a clear written record of the buyer's position for any subsequent arbitration or litigation; it may trigger the supplier's legal review, bringing a more rational commercial assessment; and it starts the clock on the supplier's response, which can be useful in establishing unreasonable delay or bad faith. A well-drafted demand letter identifies the contractual provisions breached, specifies the performance demanded, sets a reasonable deadline (typically 7-14 days), and notifies the supplier that the buyer reserves all rights including to claim damages for all losses arising from the breach. If the supplier ignores the demand, this strengthens the buyer's position in subsequent proceedings.
Not a PO alone. Include fixed price duration, quality standards, BOM, and NOM clause.
Tie price adjustments to objective, published indices -- not supplier assertions.
Attach approved BOM as contract annex. Require written approval for any substitution.
All changes must be in writing, signed by both parties, with impact assessment.
No oral modification, no waiver by course of dealing, written amendments only by authorized signatories.
Framework agreement prevails over POs, sales confirmations, and all other transaction documents.
List liquidated damages, right to cover purchase at supplier's cost, and right to terminate.
Respond in writing within 24-48 hours rejecting any attempted modification. Silence can be deemed acquiescence.
A German automotive aftermarket buyer ordered precision-machined components from a Ningbo supplier at EUR 4.80/unit, issuing a PO for 50,000 units with 30% deposit. After the deposit was paid, the supplier claimed "steel prices increased 40%" and demanded EUR 5.80/unit. The buyer's purchase order contained no price adjustment mechanism, no NOM clause, and no specified consequences for refusal to perform. The supplier halted production. After three weeks of standoff -- with the buyer's assembly line approaching shutdown -- the buyer compromised at EUR 5.30/unit. A framework agreement with a COMEX steel-indexed price adjustment clause and clear breach remedies would have either prevented the demand or given the buyer a credible threat of legal action.
A US furniture brand specified solid oak for a line of dining tables from a Vietnam-based Chinese-managed factory. The supplier substituted rubberwood (a significantly cheaper hardwood) stained to resemble oak, without disclosure. The substitution was discovered six months after delivery when a customer's furniture repair technician identified the wood species. The buyer's contract had no BOM annex and no material testing rights. The supplier argued that rubberwood was "functionally equivalent" and that the buyer had accepted the goods without timely objection (CISG Article 39 notice period). The buyer ultimately absorbed the cost of customer refunds and brand damage, lacking the contractual evidence to pursue recovery.
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