* Divestment would form part of Repsol debt-reduction plan (Recasts with Repsol statement, share price, background): * Divestment would form part of Repsol debt-reduction plan (Recasts with Repsol statement, share price, background) MADRID, Jan 10 (Reuters) - Spain’s Repsol, currently trying to reduce its debt, said on Wednesday buyout group CVC and others were interested in its 20 percent stake in local utility Gas Natural, which has a market value around 4.1 billion euros ($4.9 billion). The company said no agreement has yet been made on the stake.