TOKYO (Reuters) - Private equity firm Blackstone Group BX.N said on Tuesday it would launch a tender offer for Unizo Holdings 3258.T at 5,000 yen a share, doubling down on its $1.6 billion offer after the proposal was rebuffed by the Japanese hotel chain.

FILE PHOTO: The ticker and trading information for Blackstone Group is displayed at the post where it is traded on the floor of the New York Stock Exchange (NYSE) April 4, 2016. REUTERS/Brendan McDermid/File Photo

The potential bid from one of the world’s largest buyout funds marks another twist in the takeover saga surrounding the once-obscure hotelier, now seen as a test case for Prime Minister Shinzo Abe’s push for greater transparency and corporate disclosure.

Unizo last week rejected a buyout proposal from Blackstone as well as one from a "locally renowned" fund that it did not identify. Prior to that, Unizo withdrew support for a white-knight bid from SoftBank-backed 9984.T Fortress Investment Group. It had earlier been a target for travel agent H.I.S. Co 9603.T in a failed hostile bid.

Unizo had frustrated some investors by welcoming Fortress’s bid and then back-tracking.

Last week, Unizo’s biggest shareholder, Elliot Management, went public for the first time to ask Unizo’s board to address its concerns about disclosure in relation to Unizo’s sudden withdrawal of support for the Fortress bid.

Blackstone said in a statement it would offer 5,000 yen a share for Unizo, valuing the hotel chain at around 171.1 billion yen ($1.6 billion). That represents a slight premium to Unizo’s closing price of 4,700 yen and a sharp premium to Fortress’s proposal of 4,000 yen.

Blackstone said it would consider “any possible options” including initiating the bid if Unizo would not agree with its proposals by Oct. 23.

A Unizo spokeswoman said the company had received the offer from Blackstone but it had not decided yet how to respond.

Unizo, which operates limited service hotels in Japan, has proved attractive to bidders because of perceptions that it is undervalued. UBS analysts have previously calculated Unizo’s net asset value - a measure of an entity’s net value - at more than 7,800 yen a share after taxes.

Unizo has spurned potential bidders and pulled its support for Fortress by citing their failure to deal with Unizo’s concerns about employment.

Blackstone has said it would maintain or improve employment conditions and provide benefits which most of Unizo employees have not received yet, such as owning Unizo stock and getting incentive payment systems.

Blackstone has opposed Unizo’s plan to create a scheme where Unizo employees could exercise control over a new owner’s ability to later exit.