There is no legal requirement in many countries for a company to report it has been hacked and even if there were, if they dont spot the hack how can they report it? See No Evil, Hear No Evil, Speak No Evil, problem solved. Beside with so many global businesses employing the best from around the world, how do these companies know they are not employing spooks with excellent fabricated grades? It might explain how Microsofts Win10 source code their crown jewels, was leaked online.
GPDR or whatever it's called requires it. So pretty much the entirety of the EU... Or companies with offices in the EU ... So if you're an EU citizen, you should have been notified by law.