(Reuters) - Power producer Duke Energy Corp DUK.N said it was looking to sell all or part of its international unit, a year after the company reviewed the business and decided to stick with it.

Duke, the largest U.S. power company by generation capacity, said it was yet to receive an offer for the unit.

The move is part of the company's attempt to reduce exposure to unregulated markets in the United States and internationally, and follows its $4.9 billion purchase of natural gas distributor Piedmont Natural Gas Co PNY.N.

Duke’s international business - which spans Brazil, Argentina and Chile - had earned only half of what the company had expected through September, Duke said in its last quarterly report.

The unit accounted for about 12 percent of the company’s revenue in the three months ended Sept.30.

Duke’s 25 percent equity investment in Saudi Arabian National Methanol Co will not be a part of the potential transaction, the company said on Thursday.

Duke, which is expected to report fourth-quarter results later this month, cut the top end of its 2015 profit forecast in November, citing a drought and a slowing economy in Brazil.