Regarding the UNH criminal probe, look at the WellCare fraud for clues of the Armageddon scenario.

Back in 2007, criminal charges were bought against WellCare and its executives for defrauding Florida's Medicaid program.

https://www.justice.gov/archives/opa/pr/four-former-wellcare-executives-found-guilty-florida

It's stock ticker is WCG, and you can find a historical chart here:

https://www.barchart.com/stocks/quotes/WCG/interactive-chart

In October 23, 2007, the Justice Department announced charges against the company and the stock dropped from $115 to $20 over a few days, a loss of 82%. It eventually stabilized in the $30 range before going back down into the single digits during the Great Recession. However, it recovered back to its previous price levels by 2017 and reached $350 in 2021 before being acquired.

So... if the worst happens to UNH (e.g., criminal probe where charges are filed and the government brings the hammer against the company and wins), expect this to go way below $200 and stay there for a long time.

But of course, such prosecution of corporate fraud is quite rare so take that as you will. I think UNH will ride this one out as it's too big to fail.