By Marc Alexander

What Microsoft requires.

Microsoft Advertising's tag, Universal Event Tracking or UET, is what records conversions and builds remarketing lists for Bing ads. In March 2025 Microsoft told advertisers with visitors in the EEA, the UK and Switzerland to implement UET consent mode by 5 May 2025.

Without it, UET stops recording conversions and updating remarketing lists for those visitors. The ads keep running; the measurement behind them goes dark.

The mechanism is simpler than Google's. There's one value, ad_storage, which must be set on every page load before the UET tag runs, and updated when the visitor makes a choice. In the three regions it defaults to denied, so a site that sends nothing is treated as unconsented. Elsewhere it defaults to granted.

Google's signals are read by Google's tags. UET is Microsoft's tag and reads its own setting. A consent manager that sets Google's four values and stops there leaves UET on its denied default for every European visitor, however many people accepted the banner.

Most consent platforms added Microsoft support during 2024 and 2025, but it's usually a switch to turn on rather than something that happens by itself, and a Tag Manager setup built by hand needs the code added.

Setting it up in Tag Manager.

  1. Set the default in a tag that fires before UET on every page: ad_storage denied.
  2. Update on consent. When the visitor accepts advertising cookies, push an update setting it to granted; the consent manager's event is the trigger.
  3. Fire UET after the default, never before. Tag sequencing or a consent initialisation trigger handles the order.
  4. Test it. Microsoft's UET tag helper shows the consent value the tag read.

Treat the Microsoft update as part of the same consent flow as Google's, so one "accept" moves both. A visitor who accepted advertising once shouldn't be asked twice.

The wider point.

Each advertising platform now has its own consent mechanism: Google's Consent Mode, Microsoft's, Meta's Limited Data Use settings and its EU terms, and TikTok's.

A consent manager is only doing its job when the visitor's choice reaches all of them, which is one reason a consent setup is worth testing platform by platform rather than trusting the banner. Consent Mode v2 for EEA traffic covers Google's side, and Consent Mode v2 for UK websites explains why UK visitors are included.

What to check.

  1. Does the site advertise on Microsoft at all? Look for the UET tag in Tag Manager or in the page source.
  2. In the browser, before touching the banner: has ad_storage been set to denied for UET?
  3. Accept advertising, and check it flips to granted.
  4. In Microsoft Advertising, check the UET tag's consent status in the conversion tracking reports.

Marc Alexander sets up consent and Consent Mode across Google, Microsoft and Meta for European businesses, with prices in euros, and the Consent Mode v2 testing guide shows how to check Google's side.