By Edhi Pranasidhi and Eric Bellman

JAKARTA--Recapital Advisors Chairman Rosan Perkasa Roeslani, one of the largest shareholders in Bumi PLC (BUMI.LN), said his fund is willing to accept Bakrie Group's $1.2 billion offer for the London-listed company's coal mining assets if it is good for shareholders.

Mr. Roeslani--who is also president director of PT Berau Coal Energy (BRAU.JK), one of the companies that Bakrie is trying to buy back from Bumi--said recently the offer so far has been good for investors.

Berau shares have risen as much as 63% since Bakrie's offer was unveiled last week, while Bumi PLC shares have climbed as much as 20% over the same period.

Support from his fund will likely improve the chances of Bumi's shareholders approving Bakrie's offer.

"Our voting rights in Bumi PLC are quite substantial and will be used to recover the value of shareholders, protect the company from destructive efforts, guard Indonesia's assets and its coal industry and increase the value of Indonesia coal assets," Mr. Roeslani told Dow Jones Newswires.

"What is certain is the market has responded well to the offer."

Recapital, which owns about 13% in Bumi PLC, is the company's third-largest shareholder after the Bakrie Group and Samin Tan's PT Borneo Lumbung Energi & Metal (BORN.JK), which each have a 23.8% stake.

In 2011, Recapital folded Berau into Bumi PLC in the hope of raising its market value, but Mr. Roeslani said the value of the Bumi shares it received in exchange for its assets have plunged.

"Initially, Recapital's plan to join Bumi PLC was aimed at increasing the value of Berau's shareholders," he said. "The plan, however, hasn't worked as expected and negatively impacted Berau shares."

Recapital is considering whether it can get better value for its assets if they are taken out of Bumi PLC, he said. Last week, Bakrie said it plans to buy Bumi PLC's stake in Berau.

In Bakrie's buyback proposal issued Thursday, the influential Indonesian conglomerate would give up its 23.8% stake in Bumi PLC in exchange for a 10% stake in Indonesia-listed Bumi Resources.

Bakrie Group plans to buy Bumi PLC's remaining 18.9% stake in the Indonesian unit for $278 million after the initial deal, and also aims to buy Bumi PLC's other mining asset--an 85% stake in Berau--for about $950 million.

If completed, the deals would leave Bumi PLC without mining assets.

Analysts and investors said they expect Recapital to side with the Bakrie Group. Mr. Roeslani and Recapital received a $500 million loan from Bumi Resources.

Nat Rothschild, the British financier who resigned from Bumi PLC's board Monday, had been campaigning to have the loan repaid to lighten Bumi Resources's debt load.

Write to Edhi Pranasidhi at edhi.pranasidhi@dowjones.com and Eric Bellman at eric.bellman@wsj.com

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