Steinway Musical Instruments (LVB) agreed Monday to be acquired by private equity firm Kohlberg & Co. for $438 million in cash.

The 160-year-old maker of Steinway & Sons pianos and other instruments will be taken private for $35 a share, a 15% premium over Friday’s close.

Shares were trading 15.2% higher at $35.06 early Monday morning. As of Friday, the stock was up 43% on the year.

Under the agreement, Steinway will begin a go-shop period of 45 days. During this time, Steinway can seek alternative offers.

Steinway said its board unanimously approved of Kohlberg’s offer and recommends that shareholders tender their stock. Any shares not tendered will be acquired in a second-step merger at the same price of $35 a share.

The company expects the transaction to close in the third quarter.

In May, Steinway reported a first-quarter profit that quadrupled on a gain from selling its stake in the Steinway Hall building. However, revenue fell 1.5% during the period.

Follow Matthew Rocco on Twitter @MatthewRocco