In a statement posted on its official Twitter account, Instagram said that it has not made any recent changes to the way its feed algorithms work and that "we never hide posts from people you're following - if you keep scrolling, you will see them all."
Instagram explained that the order of posts in a feed is determined by the level of user interaction – in other words, like its parent network Facebook, posts on Instagram are organized by potential level of engagement rather than in chronological order.
What shows up first in your feed is determined by what posts and accounts you engage with the most, as well as other contributing factors such as the timeliness of posts, how often you use Instagram, how many people you follow, etc.— Instagram (@instagram) January 22, 2019
We have not made any recent changes to feed ranking, and we never hide posts from people you're following – if you keep scrolling, you will see them all. Again, your feed is personalized to you and evolves over time based on how you use Instagram.✌️— Instagram (@instagram) January 22, 2019
After the algorithm though, Instagram's users see 90 percent of their friends' posts. Given those figures, recent rumors that the platform have been limiting the reach of posts could just well be the result of some users not scrolling down far enough.