Somnigroup Seeks to Buy Leggett & Platt for About $1.6 Billion

Somnigroup International has offered to buy Leggett & Platt for about $1.63 billion in an all-stock deal, a move that would add the adjustable-bed and mattress-spring maker to its bedding empire.

Somnigroup, formed from Tempur-Sealy’s acquisition of Mattress Firm, on Monday proposed to acquire all of Leggett & Platt’s outstanding shares for $12 apiece. The price represents a roughly 30% premium to its average closing price over the past 30 days, the mattress maker added.

The all-stock structure would enable Leggett & Platt shareholders to participate in the future growth potential of the combined company on a tax-deferred basis, according to Somnigroup.

Shares of Leggett & Platt jumped 13%, to $11.59, in premarket trading.

Leggett & Platt said it will carefully review and evaluate the unsolicited proposal to determine the course of action that it believes is in the best interests of the company and its shareholders.

The Carthage, Mo., company makes furniture, engineered components and products for homes, offices, automobiles and commercial aircraft, including bedding products such as mattress springs, specialty foam, adjustable beds and machinery.

Somnigroup Chief Executive Scott Thompson said Leggett & Platt has been an important supplier of the company for many years.

Under the deal, Leggett & Platt would continue to operate independently under the Somnigroup umbrella, which includes Tempur-Pedic, Sealy, Stearns & Foster and Sleepy’s brands.

Somnigroup said the company would benefit from having a substantial and reliable customer in Tempur Sealy, as well as a lower cost of capital and strategic backing. It said it would expect to retain most of Leggett & Platt’s management team and employees, as well as a significant presence in Carthage.

Write to Connor Hart at Connor.Hart@wsj.com