NEW YORK (Reuters) - Arconic Inc ARNC.N Chief Executive Officer Klaus Kleinfeld, under pressure from hedge fund Elliott Management, on Wednesday defended the metal maker's performance since spinning off from aluminum producer Alcoa Corp AA.N.

Klaus Kleinfeld listens during a session in the Swiss mountain resort of Davos in a January 23, 2015 file photo. REUTERS/Ruben Sprich/Files

Elliott on Tuesday nominated five directors to Arconic’s board, taking aim at Kleinfeld’s leadership, company strategy and its performance compared to peers.

“The board, as well as management, have had intense dialogue with Elliott and spent countless hours to go through those assertions,” Kleinfeld told network CNBC in an interview on Tuesday. “The board stands behind the strategy and they stand behind me.”.

On Tuesday, Arconic announced the board unanimously backed the CEO, a sign the company was digging in its heels against Elliott, making it more likely the fight over Kleinfeld and the company’s path could go to a shareholder vote this spring. Arconic spun off from aluminum producer Alcoa last November in a move orchestrated by Kleinfeld.

With any proxy fight, the two sides can reach an agreement all the way up to the final hour of the vote. Arconic’s annual meeting is usually in May.

Arconic’s stock soared to $25 on Wednesday, as investors bet that Elliott’s pressure will drive the stock even higher.

Prior to Elliott’s nominations, Arconic’s shares had risen from $17 late last year to around $22.

After the split, Alcoa retained the company’s legacy aluminum, alumina and bauxite smelting business, while Arconic focused on higher-end aluminum and titanium alloys used in planes and cars.

“Each Arconic business will massively miss the performance targets that management set for 2016,” Elliott said in its presentation, sent to shareholders on Wednesday.

Kleinfeld on Wednesday told CNBC that margins were improving and the business has come a long way since the commodity market plunge in 2009 nearly sank Alcoa.

Elliott has said Larry Lawson, formerly CEO of Spirit AeroSystems Holdings Inc SPR.N should be the CEO of Arconic.

Elliott first invested in Alcoa in 2015, and struck a deal with the company prior to its Arconic spin-off, which avoided a proxy fight and allowed three Elliott-supported directors to serve on the boards of both companies.

Six of 12 independent directors on Arconic’s board joined within the last year, which includes Elliott’s three nominees and three appointed after the separation last November.