(Reuters) - DuPont (>> E I Du Pont De Nemours And Co) forecast lower-than-expected revenue and profit for 2015, joining a growing list of large U.S. corporations that have warned of a stronger dollar hurting earnings.

Shares of the company, under pressure from activist investor Nelson Peltz to improve shareholder returns, fell as much as 3.5 percent to $71.50.

DuPont, which generates 60 percent of its sales outside the United States, said a strengthening dollar would cut its full-year profit by 60 cents per share.

The company forecast 2015 operating earnings of $4-$4.20 per share, and said it expects sales "to be even with" 2014's $34.72 billion.

That forecast fell short of the average analyst estimate of a profit $4.46 per share and sales of $36.69 billion, according to Thomson Reuters I/B/E/S.

Several companies, including Caterpillar Inc (>> Caterpillar Inc.), Microsoft Corp (>> Microsoft Corporation) and Procter & Gamble Co (>> Procter & Gamble Co), have blamed the stronger dollar for their weak results and outlook.

The dollar <.DXY> has surged nearly 20 percent against a basket of major currencies after hitting a 6-1/2 month low in May.

Peltz criticized DuPont in January for lowering or missing its own forecasts for three years in a row. He nominated himself and three other members of his Trian Fund Management LP to DuPont's board this month, launching a proxy fight.

DuPont's 2015 forecast includes the performance chemicals unit, which is expected to be separated by July. The company said it plans to buy back up to $4 billion of shares using the dividend expected from the spinoff.

The new buyback plan will be in addition to an existing $5 billion program, said a company spokesperson.

The company has already bought back $2 billion of stock under that repurchase program.

DuPont also raised its cost-reduction target by $300 million to at least $1.3 billion, which it expects to achieve by 2017.

Peltz, who has called for DuPont to split itself up, has said the company can cut as much as $4 billion in costs.

DuPont, which has repeatedly highlighted the benefits of keeping its units together, posted a fourth-quarter operating profit that matched analysts expectations. However, sales fell short due to the strengthening dollar.

The share repurchases announced on Tuesday will be made over 12-18 months following the spin off of the performance chemicals unit, DuPont said.

The company's shares were down 1.6 percent at $72.95 in afternoon trading.

(Additional reporting by Manya Venkatesh; Editing by Sriraj Kalluvila)

By Swetha Gopinath