A group of bondholders of bankrupt Elpida Memory Inc. objected Tuesday to U.S. chipmaker Micron Technology Inc.'s plan to buy the Japanese chipmaker, saying its corporate value has been underestimated, and submitted its own rehabilitation plan to the Tokyo District Court.

In that reorganization, the group of around 20 financial institutions, mainly consisting of overseas firms, said it will grant Elpida a borrowing facility of ¥30 billion to provide the company with an opportunity to find another rehabilitation sponsor.

Under the agreement announced last month by Micron and Elpida, the major U.S. chipmaker would acquire the entire stake in the only Japanese maker of dynamic random access memory chips for ¥60 billion, and the Japanese company will receive ¥140 billion through 2019 from Micron for providing foundry services as a subsidiary of the U.S. chipmaker.

The group said in a statement it values Elpida at "no less than ¥300 billion," claiming Micron's purchase of the Elpida stake for ¥60 billion was "totally inadequate, grossly unfair to creditors and other stakeholders and must not be allowed."

As for the ¥140 billion that Elpida is to receive in addition to ¥60 billion from Micron, the group said, "Micron has provided no guarantee that these payments will ever be made."

The bondholders will ask the Tokyo court to certify their plan for a creditor vote expected to take place in October. Elpida aims to submit its rehabilitation plan to the court by Aug. 21.