Midsize brokerage house Maruso Securities Co. filed a petition Tuesday with the Tokyo District Court for permission to start voluntary bankruptcy proceedings, court officials said.

The Tokyo-based brokerage, which is said to have collapsed under some 44 billion yen in liabilities, was ordered by the court Tuesday to start securing its property today and to halt all regular business, with exception of returning customer assets.

Maruso's unconsolidated pretax balance when it closed its books March 31, 1997, was a loss of 1.48 billion yen, marking its third consecutive year in the red.

Securities industry sources said that efforts to ensure that all cash, securities, and other assets being held by Maruso for customers will be returned with the help of 2 billion yen from the Compensation Fund for Safekeeping Securities Inc.

However, the firm's chairman, Masahisa Hayashi, said at a news conference that approximately 3.4 billion yen of some 60 billion yen in assets entrusted to the broker as of the end of September may not be returnable.

The securities industry has been racked by a string of financial institution collapses since November. Maruso now joins Yamaichi Securities Co. and Sanyo Securities Co. to become the fifth brokerage house failure this year.