Sotera Health's (SHC) board was urged by shareholder Firstlight Management to sell the company's Nelson Labs subsidiary, according to Firstlight's letter released Wednesday.

In its Dec. 3 letter to Sotera's board, Firstlight said Sotera has "an opportunity to create an enormous amount of shareholder value" by beginning a sale of the subsidiary and concentrating its portfolio in other businesses.

"While Nelson Labs should be a good business, it has struggled under Sotera ownership," Firstlight said. "A Nelson Labs sale would result in a higher-quality, higher-growth business with substantially less leverage, higher earnings, and a more focused management team."

Firstlight estimated that Sotera would net about $1 billion from the sale of Nelson Labs and said it would welcome a conversation with management over the issue.

Sotera did not immediately reply to MT Newswires' request for comment.