There is no single look-back period for every price display. Discount advertising uses the lowest price applied in the 10 days before the promotion starts. Physical price labels and price lists are separately subject to the 30-day lowest-price rule in the Price Tag Regulation. Identify the channel and claim before calculating a discount.
How is the previous price determined for a discount?
The amendment announced by the Ministry of Trade and effective from 1 August 2026 updated the reference price for consumer discount advertising. For advertisements concerning goods, use the lowest price applied during the 10 days before the discount begins. The advertised discount rate must correspond to that reference; a brief price increase should not be used to create an inflated discount claim.
This does not turn every sales record or every price label into a 10-day calculation. In particular, do not treat an in-store label and an online advertisement as if they were governed by one identical rule. The Price Tag Regulation continues to provide a 30-day lowest-price rule for labels, tariffs and price lists. Assess the display in light of its channel and claim.
The difference between advertising and an in-store label
Previous 10 days
For an advertisement concerning goods, the lowest price applied during the 10 days before the promotion starts is the pre-discount reference. Review claims in social media, on websites, in email and in campaign creatives against this advertising rule.
Previous 30 days
The Price Tag Regulation requires the before- and after-discount prices to be shown together, visibly and legibly on applicable labels, tariffs and price lists. As a general rule, the previous price is determined using the lowest price applied during the preceding 30 days.
Important: This is a general explanation. A campaign may involve advertising, an in-store label, a particular product type and specific conditions at the same time. Review the actual presentation against the current legal text.
Example: why can the reference differ within one campaign?
The following is a fictional, currency-free price index used only to illustrate the two look-back periods. It is not a product price or legal opinion. Assume the lowest applied value in the 30 days before the campaign is 100, the lowest value in the last 10 days is 120, and the campaign price is 100:
Under this assumption, the advertising reference is 120, so a price of 100 represents an illustrative discount of about 16.7%. If the lowest price during the previous 30 days for the in-store label is 100, presenting 120 as the pre-discount label price does not produce the same result. The example shows why channel-specific price history and the exact discount claim must be checked. A real campaign must use verified records for the product.
What should be checked in conditional promotions?
The amendment also brings advertisements offering a discount or similar benefit subject to a condition within the discounted-sales rules. For claims such as “on the second item,” “above a basket value,” “with membership” or “with a specified payment method,” consumers should be able to understand the qualifying condition and which products are included. The main claim and material exceptions should be clear and accessible.
Promotion scope
Which products, variants, stores, online channels or customer groups qualify? State exclusions and any quantity limit where stock is restricted.
Condition and benefit
If the offer requires membership, a basket threshold, a quantity or a payment method, explain the condition alongside the benefit. Do not combine multiple discounts in a way that overstates the final saving.
A six-step publication check for store and e-commerce teams
Fix the product and variant
Link the promotion to the product barcode and its size, colour or model. Do not mix price histories for similar products.
Identify the channel and display
Is this a web advertisement, an in-store label, a price list or more than one display? Check the applicable basis for each format separately.
Select the correct look-back period
Match the last 10 days of records for advertising and the previous 30 days for a price tag/list to the applicable rule and product type. Check for exceptions.
Verify the lowest price actually applied
Do not rely solely on a list or recommended price. Verify the date, sales channel and consumer-facing price with records showing what was actually applied.
State conditions, dates and exclusions
Clearly and legibly state the campaign dates, scope, material conditions and exclusions, and any limited quantity.
Review every live channel
Do the product page, basket, ad creative, email and store label show consistent terms and accurate prices? Update all affected content together when a campaign changes.
- Product identifier and channel price history match.
- The pre-discount reference was checked under the correct look-back rule.
- Promotion dates and scope are visible.
- Conditions, exclusions and stock limits are clear.
- The published creative and product page show consistent prices.
- Price history and approved advertising version have been retained.
Why retain price and campaign records together?
A product price may change at different times in a store, on an e-commerce site and on a marketplace. Link the SKU/barcode, sales channel, effective time, promotion period, conditions and published creative to the same product record. If a discrepancy arises, you need to establish what price was shown, where and when.
For connected store and online inventory/price records, see our guide to store and e-commerce alignment. Discount authority, approval and profitability controls are separate topics; read our article on discount authority and approval management. These resources do not claim that an advertisement is legally compliant or that software automatically ensures compliance.
Frequently asked questions
Is the reference period 10 or 30 days for a discount advertisement?
For an advertisement concerning goods, the lowest price in the preceding 10 days applies under the new rule. The 30-day rule for price tags, tariffs and lists is a separate context; distinguish the display formats.
Should the promotion start and end dates appear in the advertisement?
The Ministry lists missing start and end dates among problematic practices. State the promotion period and any product or quantity limits clearly.
Do conditional promotions also fall under discount-ad rules?
Consumer advertisements offering a discount or benefit subject to a condition are also covered by the amendment. State membership, basket, quantity or payment conditions alongside the main claim.
Which price applies to services and perishable goods?
The Ministry’s explanation says advertisements for services and perishable goods such as fruit and vegetables use the price immediately before the discounted price. Check the current provision for the product/service and display involved.
This article is general information, not legal advice or approval of a promotion. Before publication, review the current regulation, product type and advertising/label format with a qualified adviser.
Official sources
Official sources were checked on 8 November 2026: the Ministry’s 29 July 2026 announcement, its 28 October notice on November promotions, and the Price Tag Regulation. Recheck current texts before implementation because campaign conditions and rules may change.