Facebook has announced that it will soon implement limits on how many ads a Page can run at any time. As part of its latest Graph and Marketing API update. facebook explained that in the mid-2020, they will be '' implementing a limit on the number of ads each Page can run at the same time. The ad limits will impact just a small percentage of advertisers, and we plan to share more details about the limits early next year."
Which seems weird right? Why would Facebook actively limit its revenue potential by restricting how much money a brand can spend on ads?
According to Facebook:
We’re implementing ad limits because very high ad volume can hinder an advertiser’s performance. With too many ads running at the same time, fewer ads exit the learning phase and more budget is spent before the delivery system can optimize an ad’s performance."
So, according to Facebook, running too many ads leads to worse overall ad performance. Which could, eventually, reduce overall ad spend because effectiveness is impacted -if more big advertisers start to complain about poor Facebook ad results, that could slow all advertisers in their spend.

At least, that appears to be the theory.
As noted by Facebook, the change will only impact a small number of brands, so it's not likely that your business will be affected. Marketers will be able to monitor their Page’s ad volume via the new Ad Volume API, with the change going into effect mid-2020. Expect further details before then.
Other changes being implemented in this API update include the removal of several video ad metrics and some updates to the messaging options for businesses.