Rothschild set up Bumi two years ago with the influential Bakrie brothers, when his investment vehicle Vallar took over their Indonesian coal assets.
But relations between them have soured, and in September Bumi launched an investigation into alleged financial irregularities at the Indonesian arm.
Then last month the Bakrie family proposed cancelling their shareholding in London-listed Bumi and taking back the coal assets they brought in two years ago, essentially dismantling the firm. These proposals are currently being considered by the Bumi board.
However, London-listed Bumi today confirmed it had not received a proposal from the financier.
A spokesman for Nat Rothschild declined to comment.