UnitedHealth’s stock chops more than 230 points off the Dow’s price

Shares of UnitedHealth Group Inc. took a dive Wednesday toward their worst percentage performance in more than three years, after the health insurer said it was facing higher costs from pent-up demand for surgeries.

The stock UNH was by far the biggest decliner within the Dow Jones Industrial Average DJIA, and was among the worst performers in the S&P 500 SPX, along with fellow health insurers with Medicare Advantage exposure.

UnitedHealth’s…