[ballenf]

There are clear-ish rules for when you need to report the transaction and seek clearance in advance. They come down to transaction size, I believe. But the DOJ/FTC can sue to block any transaction on antitrust grounds, whether reportable or not.

There are no rules that block any particular acquisition, just rules about whether you need to preemptively notify the government about the transaction and give them time to decide whether to challenge it.

[texasbigdata]

Here is likely what you’re referring to. Above ~~$75M it has to be declared and then you are subject to review.

https://en.m.wikipedia.org/wiki/Hart–Scott–Rodino_Antitrust_...