Microsoft Advertising has expanded seasonality adjustments to support campaigns using portfolio bid strategies. This feature enables advertisers to apply adjustments for short-term events, such as major promotions or seasonal peaks, to all campaigns within a portfolio.
Advertisers are recommended to use a consistent adjustment across all campaigns to avoid aggressive rebalancing of spend.
This update applies to tROAS and tCPA campaigns and is meant for significant changes, not for normal performance optimization during learning periods.
You can read the official announcement here: Performance Max Updates and Other Product News for April 2026.