The impact of the failure of Toshoku Ltd. has begun to ripple through a number of banks and other firms who either deal with or hold shares in the medium-size trading company.

Toshoku, which deals mainly in foodstuffs, filed for court protection from its creditors under the Corporate Rehabilitation Law. Its liabilities total some 639.7 billion yen.

On Friday, the key Nikkei stock price average on the Tokyo Stock Exchange registered its third largest single-day point loss this year on increased fears of credit risks following the failure of the trading house. Immediately after it filed for protection, Sakura Bank and Yasuda Trust & Banking Co., two of its major shareholders, said they would write off their bad loans to Toshoku by March 31. Sakura said its outstanding loans to both Toshoku and subsidiary Toshoku Finance total 164.8 billion yen, of which it expects 124 billion yen to be irrecoverable.

Toshoku Finance incurred much of its bad loans and losses after actively extending loans and using borrowers' securities holdings as collateral. In addition, the trading house itself was investing in securities, and the burst of Japan's economic bubble wiped out much of their value.

Sakura said it will quickly set aside loan-loss reserves to cover the fresh losses by selling a part of its shareholdings for latent gains. As a result, Sakura officials said the bank will not have to raise its pretax and net loss projections for the 1997 business year, which ends next March 31.

Still, Moody's Investors Service said Friday that it is reviewing Sakura Bank's credit ratings for possible downgrade, due to concern over the negative impact of Toshoku's collapse. "Moody's will focus on the extent of Sakura Bank's asset quality deterioration, including the impact of the failure of Toshoku," the credit rating agency said.

Yasuda Trust said meanwhile that its outstanding loans to Toshoku and Toshoku Finance total 37.7 billion yen. The bank said Friday that it may not recover some of the 12.7 billion yen in loans it has allowed Toshoku, and losses resulting from the bank's exposure to the trading house may reach an uncollateralized 9 billion yen for the fiscal year ending March 31.

Other major and local banks also said part of their loans to the collapsed firm may become irrecoverable. Daiwa Bank said it fears its 7.6 billion yen loans to Toshoku may not be recoverable. The bank plans to write off the loans in the current business year, but its earnings will not be affected, bank officials said.

Gunma Bank is in the same situation, with outstanding loans of 4.45 billion yen to Toshoku. The regional bank will write off the loans in the current year to March, it said. Another regional bank, Kagoshima Bank, said its irrecoverable loans to the failed trader stand at 7.18 billion yen. The bank will use 8 billion yen in profits from stock sales to write them off in the current year. Hokuriku Bank said its loans to Toshoku and subsidiary Toshoku Finance totaled 8.19 billion yen and 10.7 billion yen, respectively. Although the bank cannot exactly estimate its losses, bank officials said they will be written off this term.

Mitsui Marine & Fire Insurance Co., another major shareholder, said it will set aside loan-loss reserves of 3.5 billion yen in the year to next March in expectation of losses to the food trader. Mitsui Marine's annual earnings estimates remain unchanged because the company expects to offset the loan writeoff with profits from the sales of securities, officials of the insurer said. Mitsui Marine also plans to write off 5.1 billion yen in loans made to Toshoku Finance.