GMV Max Promotion Day: reducing target ROI by 10% does not mean your actual ROI will drop by exactly 10%

Many people misunderstand: setting a 10% lower target ROI means the actual ROI will definitely drop by exactly 10%. Incorrect. GMV Max inherently has a natural ROI fluctuation of 80-120% compared to the target — Promotion Day only changes the target number, it does not eliminate this fluctuation.

Promotion Day Mechanism

When enabled, the system prioritizes maximizing GMV during shopping seasons (Double Day, Payday…): ROI can decrease by up to 10%, and the budget increases by 50% to provide enough growth space. You can customize deeper reductions (-10%/-20%/-30%) — each reduction level has a corresponding GMV estimate, based on the category’s 14-day average GMV change data.

Worst-case scenario: doing the actual math

A question from the official documentation: if the ROI target is 10, does enabling Promotion Day mean the minimum achieved ROI is 9?

No. Because the achieved ROI of GMV Max fluctuates between 80-120% compared to the original target. Worst-case scenario: Minimum ROI = 10 × 90% (target reduction) × 80% (lowest fluctuation) = 7.2. However, usually, the actual ROI will fall around 9.

UI illustration example: selecting a -20% ROI reduction -> “Promotion days target ROI: 1.6”, “Estimated GMV +22%”, budget increased by 150% to 450 USD (from the original level).

Why you should still enable it for all GMV Max campaigns

This feature is recommended for all sellers because it automatically takes effect during recurring shopping seasons (Double Day, Payday, Ramadan, Spring Sales…), helping to capture incremental GMV when opportunities arise without manually tracking each sale day.

Frequently Asked Questions

Can I exclude a specific sale season from Promotion Day?
Yes, go to “View Details” to uncheck the shopping seasons you do not want to apply, or set up a custom time range for Category Campaigns, Super Brand Days…

Does Promotion Day affect ROI Protection?
Yes — on Promotion Day, the ad credit refund will be calculated based on the “Promotion Day Target ROI” value instead of the original target ROI.

Source

Official GMV Max guide (updated to July 2026).