U.S. investment fund Lone Star, which holds about a 70 percent of stake in Tokyo Star Bank, plans to auction off all or a major part of the stake, sources said.

Several financial institutions and investment funds, including Britain's largest bank, HSBC, U.S. investment fund TPG and domestic investment fund Advantage Partners have already expressed interest in the acquisition. Lone Star may decide a purchaser by the end of May, they said.

Lone Star acquired Tokyo Star Bank's predecessor, Tokyo Sowa Bank, in 2001 after the second-tier regional lender collapsed due to massive nonperforming loans.

Seeking a capital gain, Lone Star now wants to sell off at least more than one-third of its holdings in Tokyo Star Bank so the management rights of the bank will transfer to the purchaser, the sources said.