UnitedHealth Group Inc. CEO Andrew Witty is expected to testify this week at congressional hearings about the cyberattack, but he'll likely also face questions on whether UnitedHealth has become too big.

UnitedHealth said it paid ransom to protect patient data, following the cyberattack on its subsidiary Change Healthcare. But personal data was compromised anyway.

UnitedHealth says files with personal information that could cover a “substantial portion of people in America” may have been taken in the cyberattack on its Change Healthcare business.

So far, the company has reported advancing more than $6 billion to providers in need, "and we will continue to financially support providers through full system recovery," officials stated.

The cyberattack on Change Healthcare in February targeted the data of “a substantial proportion of people in America,” UnitedHealth Group (UHG) said this week, with the company