Dec 1 (Reuters) - Mattress manufacturer Somnigroup International said on Monday it had submitted a proposal to buy Leggett & Platt in an all-stock deal that valued the furniture and bedding maker at about $1.63 billion.

Somnigroup, which had sent a letter to the Carthage, Missouri-based company's board, said shareholders would get a Somnigroup common stock with a market value of $12 for every share of Leggett & Platt common stock.

Leggett & Platt shares jumped about 14% in morning trading.

Leggett & Platt has a market capitalization of $1.39 billion, according to data compiled by LSEG.

The company confirmed receiving Somnigroup's "unsolicited, non-binding proposal" and said its board will review the offer with its independent financial and legal advisers.

Leggett & Platt added that Somnigroup did not engage with it regarding the proposal prior to November 30.

As part of the deal, Leggett & Platt would operate independently under Somnigroup's umbrella, with most of its management team retained, Somnigroup said.

Leggett & Platt has been requested to respond to the proposal by December 22.