These are the companies that will win—or lose—from Apple’s impending user privacy change

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This spring, Apple is expected to roll out a change to its iOS 14 software that will grant users more privacy and disrupt the digital advertising ecosystem.

This change will affect a unique device identifier on every iPhone and iPad called the IDFA or the "identifier for advertisers." Companies that sell mobile ads rely on this ID to target promotions to users and estimate their effectiveness.

With the upcoming update to iOS 14, apps that want to track users will have to ask them to opt in.

This change is expected to shake up digital advertising. Here are the companies that stand to win and lose.