What share of a real marketing list sits with each mailbox provider?
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Across the lists Review My Emails has cleaned, here is how the addresses split by mailbox provider: Google (Gmail and Workspace) 46.7%, Microsoft (Hotmail, Outlook, Live) 17.4%, Yahoo and AOL 11.2% (Yahoo 9.2, AOL 1.9, Rocketmail 0.1), Apple iCloud 1.9%, security gateways in front of business mail 2.9% (Proofpoint, Mimecast, Barracuda, Cisco, Cloudmark, AppRiver), AT&T 0.8%, Comcast 0.7%, other 4.3%, and no provider detected 12.1%.
So close to half of a real list sits with Google. This is a Review My Emails finding from our own data, read on 24 Sep 2026. It is the share of addresses on real lists, which is not the same as the share of opens by email app or the share of websites using each mail server.
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