Wendy’s largest shareholder, activist hedge fund Trian partners, has signaled it is exploring a potential deal to buy the fast-food giant – a development that sent the company’s stock soaring on Wednesday morning.

Trian said it has informed Wendy’s board of directors that it is evaluating an offer, either “alone or with third parties” to buy the company to “enhance shareholder value,” according to an SEC filing. The firm said transaction could be a merger or takeover that would result in a change of control over Wendy’s.

Wendy’s shares were trading nearly 10% higher Wednesday as investors reacted to a potential sale.

Wendy’s confirmed its awareness of the Trian Partners filing, noting that its “board of directors and management team regularly review the Company’s strategic priorities and opportunities with the goal of maximizing value for all stockholders.”

“Our Board is committed to continuing to act in the best interests of the Company and its stockholders,” Wendy’s said in a statement. “Consistent with its fiduciary duties, the Board will carefully review any proposal submitted by Trian Partners.”

Trian’s leaders already exert significant control over Wendy’s operations, with three seats on its board. The hedge fund’s co-founder, billionaire Nelson Peltz, is Wendy’s chairman, while another co-founder Peter May is vice chairman.

Trian owns more than 19% of Wendy’s shares, more than any other entity, according to Dow Jones data.

Wendy’s stock has plunged more than 23% over the last 12 months.

Trian’s website notes the firm has pushed to improve Wendy’s value “by divesting ancillary brands, lowering overhead, improving restaurant operations, investing in growth and returning capital to shareholders” since it first invested in the company in 2005.

The activist push will unfold as Wendy’s and other firms contend with difficult market conditions. The chain is attempting to lure customers with new offerings, such as an expanded breakfast menu.

While global sales at company-owned stores rose 2.4% in the company’s most recent earnings report, Wendy’s noted that higher operating costs related to commodities and labor were cutting into its profit margins.

Net income fell to $37.4 million in the first quarter, down nearly 10% compared to the same period one year earler.

Despite the tough market, Wendy’s is pushing forward with plans to expand its restaurant count – with CEO Todd Penegor stating earlier this month that the company was on track to achieve net unit growth of 5% to 6% this year.

“We are well positioned to win in this volatile environment, with strong franchisee alignment behind our strategies, and have strengthened our balance sheet with the successful debt raise transaction we recently completed,” Penegor said.