This staggering figure is nearly double the previous estimate of 100 million people affected.
The stolen data trove contains a wide range of personal and medical information.
The healthcare giantrevealedthe latest numbers in an email to TechCrunch on Friday evening.
He added that the vast majority have already received individual notification or substitute notice about the breach.
It caused widespread disruptions and outages across the nation’s healthcare system for several months.
Investigators have attributed the attack to the notorious Russian cybercrime group ALPHV, also known as BlackCat.
The hackers gained initial access using a stolen account credential that lacked multi-factor authentication security, according to UnitedHealth.
The financial fallout has been severe.
The incident further illustrates how the healthcare sector remains theprimary targetfor bad actors.
