(Bloomberg) -- Toshiba Corp.’s preferred bidder won’t secure letters of commitment from banks by year-end, casting yet more uncertainty over a deal as disagreements over lending terms persist after months of negotiations.

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A consortium led by Japan Industrial Partners Inc. is in talks over bank financing totaling about 1.4 trillion yen ($10.6 billion) to take Toshiba private, but negotiations have stalled over covenants and collateral, preventing banks from deciding how much funding each would provide, people familiar with the matter said.

JIP has also requested additional subordinated loans and other forms of mezzanine capital, with talks still ongoing, the people said.

Banks including Sumitomo Mitsui Banking Corp. had expected to sign off by end-December on 1.2 trillion yen in syndicated loans to help finance the buyout deal and another 200 billion yen to cover operational costs after Toshiba’s privatization. No financing commitment is now possible until the new year, the people said.

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Sumitomo Mitsui and JIP spokespeople declined to comment.

The buyout deal is expected to be valued at around 2.2 trillion yen, and JIP plans to decide on an offer price once it secures commitment letters. Toshiba may then hold a special committee meeting in mid-January to discuss JIP’s offer, the people said.

Securing financing from banks has been a major obstacle in Toshiba’s drawn-out push to go private, in an effort to reboot one of Japan’s iconic brands sullied by years of scandals. Rising financing costs and a deterioration in banks’ trust in Toshiba’s management have thrown roadblocks to a deal.

To boost operational efficiency following the takeover and Toshiba’s subsequent delisting, lenders may ask to nominate one or more directors to the company’s board, the people said.