99 Cents Only Stores on Friday said that it has received a bid from the family that runs the company along with Leonard Green & Partners L.P. to take the company private for $1.34 billion in cash.

The Commerce-based discount retailer said it would form a special committee of independent directors to consider the proposal. The Schiffer-Gold family, which owns about 33 percent of the company, has partnered with the Santa Monica private equity firm to offer other shareholders $19.09 per share, a 14 percent premium to the stock’s closing price on Thursday.

Shares closed up 17 percent to $19.58, indicating that investors expect a higher bid. Numerous law firms have already announced they would investigate whether the bid was fair.

99 Cents Only’s co-founder and chairman is David Gold. His son-in-law Eric Schiffer is chief executive, his son Jeff Gold is president and chief operating officer, and both are directors. Another son, Howard Gold, is executive vice president of special projects.

The Schiffer-Gold family is prepared to contribute a “substantial portion” of its stock as part of the deal, according to the proposal, adding that the family has not made any commitment of exclusivity with Leonard Green relating to a transaction.

“The board of directors cautions the company’s shareholders and others considering trading in its securities that it has only received the proposal and it has not yet been evaluated,” the company said in a statement. “There can be no assurance that any definitive offer will be made, that any agreement will be executed or that this or any other transaction will be approved or consummated.”