Duke Energy says a proposal to break up its business into three regional operations would increase costs and put pressure on utility rates. The Charlotte, N.C.-based utility company said it will review Elliott Investment Management's proposal but it has rejected other offers the Florida-based hedge fund has made since last summer, according to a Duke Energy press release. The letter outlines Elliott's arguments and asks Duke Energy to appoint new board members — including among candidates that it has identified "to bring fresh perspectives" — and to establish a review committee to explore the proposal.