As Facebook is gradually limiting the organic reach of branded content, brands basically have no choice but to pay up to promote their posts.
However, according to a recent Socialbakers report, spending money alone isn’t going to do much good if the content isn’t engaging. The effect of paying for additional reach on Facebook is vastly bigger when the promoted content is good enough to evoke many interactions. While the total reach of posts with few interactions is only 2.3 times higher than the organic reach on average, the total reach of posts with more than 5,000 interactions is almost 90 times higher than the organic reach, meaning that the effect of promoting posts is strongly amplified if the level of interaction is high.
This chart illustrates how interactions with branded content on Facebook correlate with reach.
You will find more statistics at Statista