Executive summary
In BFCM 2024, CPCs rose 34% for advertisers using seasonality adjustments versus 17% for those who did not; ROAS fell 15.7% with adjustments and rose 5.7% without. The conversion value advantage from adjustments shrank from about 25 points (2022) to about 6 points (2024).
Key findings
- 34% vs 17% CPCs rose faster with adjustments
CPC increase in BFCM 2024 with and without adjustments. - -15.7% vs +5.7% ROAS moved in opposite directions
ROAS change with and without adjustments. - 25 to 6 points The adjustment advantage shrank
Conversion value advantage, 2022 to 2024. - 17.5% to 7.5% Conversion rate lift fell
Conversion rate lift without adjustments, 2022 to 2024.
Methodology
Each BFCM period, from the Wednesday before Black Friday through the Wednesday after Cyber Monday, was compared with a pre-holiday baseline, for advertisers who set seasonality adjustments versus those who did not, across 2022 to 2024.
MarTech published the analysis as sponsored content by Optmyzr on October 15, 2026.
How to read it
Optmyzr sells the tools it promotes, and MarTech says it neither confirms nor disputes the conclusions. It compares two groups of advertisers and is not a controlled experiment, so advertisers who adjust may differ in other ways. The headline says 5,000+ accounts while the body says 5,886.