What happened

Investors clearly felt UnitedHealth Group (UNH -0.04%) stock was good insurance against a slumping market on Wednesday. On the back of a recommendation upgrade from an analyst, they traded the healthcare insurer's stock up by nearly 4% on the day, providing a sharp contrast to the limp S&P 500's 0.3% slide on the day. 

So what

The analyst making the change was Raymond James' John Ransom. He moved his UnitedHealth recommendation one peg higher to strong buy from his previous outperform (buy, in other words). In doing so, he also added a handful of dollars to his price target; this now stands at $630 per share, up from $615. At the current market price, this implies potential upside of 24% even after Wednesday's bump.

UnitedHealth wasn't the only healthcare insurer receiving a push higher from Ransom. He also did the same outperform to strong-buy recommendation upgrade for Cigna, placing a price target of $350 per share on that company's stock.

These moves follow Ransom's downgrading of health insurance stocks like UnitedHealth and Cigna last December.

"We were concerned about the overhang of some complicated regulatory actions...suffice to say these were cleared up in early April," Ransom told CNBC in an interview about his changes.

Now what

That clarity came from Federal authorities; on Monday the Biden administration published a new set of Medicare rules, which included the program's relationship with Medicare Advantage providers like UnitedHealth. Investors were cheered by the fact that aggressive regulations aimed at preventing overbilling are not being as forcefully implemented as many insurers had worried.