Today was the day of the largest ever purge of Instagram accounts. This is nothing new since Instagram does this once or twice each year - but not on this scale.
The reason behind these annual account purges is to rid Instagram of at least a portion of the inactive and bot accounts inflating its percieved user base.
Although official figures aren't out yet we estimate that at least a 100 million instagram accounts have been removed.
UPDATE: The Official statement from Instagram that they are "working to resolve" the issue. They might just have deleted a bit too many inactive accounts and didn't expect this level of public outcry.
We’re aware of an issue that is causing a change in account follower numbers for some people right now. We’re working to resolve this as quickly as possible.— Instagram (@instagram) February 13, 2019
UPDATE 2: Some accounts seem to gotten their followers back like @9gag and @kyliejenner. Maybe it was a bug after all? We suspect that Instagram's chache might have been accidentally rolled back a couple of days.
Here are the top 5 accounts that lost the most followers:
@Selenagomez lost 2.3 million, 1.58% of her followers
@9gag lost 1.1 million, 2.41% of its followers
@kyliejenner lost almost 2.5 million, around 2% of her followers
@arianagrande lost 2.3 million, 1.6% of her followers
@cristiano lost 2.3 million, 1.5% of his followers
How many followers have you lost?