Tech giants including Facebook, Google, Twitter and TikTok face stricter online content rules in the European Union due to their huge number of users.
The new rules, known as the Digital Services Act (DSA), classify companies with more than 45 million users as very large online platforms (VLOPs) and require them to do risk management and external and independent auditing.
They will also have to share data with authorities and researchers and adopt a code of conduct.
The European Commission had given online platforms and search engines until Feb. 17 to publish their monthly active users. Those labelled as VLOPs have four months to comply with the rules or risk fines.
Twitter on Thursday said it had 100.9 million average monthly users in the EU, based on an estimation of the last 45 days.
Google owner Alphabet provided one set of numbers based on users' accounts and another set based on signed-out recipients, saying users can access its services whether they sign in to an account or are signed out.
It said the average monthly number of signed-in users totalled 278.6 million at Google Maps, 274.6 million at Google Play, 332 million at Google Search, 74.9 million at Shopping and 401.7 million at YouTube.
Apple said only its App Store built for its iPhones, with more than 45 million monthly users, qualified as a very large online platform. But it will also apply the same rules to the App Store for iPads, Mac computers, Apple Watch and TV, and to its Apple Books e-books and podcasts paid subscriptions.
"Apple intends, on an entirely voluntary basis, to align each of the existing versions of the App Store (including those that do not currently meet the VLOP designation threshold) with the existing DSA requirements for VLOPs," it said on its site.
Amazon said it had more than 45 million users in the EU, while Microsoft said its Bing search engine had 107 million average monthly users in the last six months of 2022.
Alibaba Group Holding's e-commerce site AliExpress said its average monthly active users in the EU was above 45 million from Aug. 1 last year to Jan. 31 this year.
TikTok has 100.9 million average monthly users in the EU based on an estimation of the last 45 days.
Ebay said it was below the EU user threshold.
Meta Platforms has said it had 255 million average monthly active users on Facebook in the EU and about 250 million average monthly active users on Instagram in the last six months of 2022. Companies will have to report user numbers every six months.