A bankruptcy court judge on Wednesday said she may rule by next month on efforts by Washington Mutual Inc to get back more than $4 billion in cash deposits to which it lost access when the bank was sold to JPMorgan Chase & Co last year.

U.S. Bankruptcy Judge Mary Walrath said at a brief court hearing in Wilmington, Delaware, that she may decide on Washington Mutual's request for summary judgment on the matter before a June 24 scheduled court hearing.

Washington Mutual contends in court papers that JPMorgan is withholding deposits without any legitimate basis.

Washington Mutual Bank was closed by the U.S. government in September, in one of the largest bank failures in U.S. history.

Its banking assets were sold the same day to JPMorgan for $1.9 billion, and the parent holding company filed for bankruptcy protection a day later in Delaware.

WaMu has said that JPMorgan improperly claims it acquired the $4 billion in deposits as part of the takeover but that this money should have been treated like any other deposit at the bank.

WaMu has said it needs access to that cash to come up with its Chapter 11 plan, and that by withholding the deposits, JPMorgan could be earning as much as $200 million per year in interest.

A JPMorgan Chase spokesman said the company had no comment.

The lawsuit was filed as an adversary proceeding to WaMu's main bankruptcy case.

The bankruptcy case is In re: Washington Mutual, Inc. U.S. Bankruptcy Court, District of Delaware, No. 08-12229.

(Reporting by Jessica Hall; writing by Martha Graybow and Chelsea Emery; editing by Gerald E. McCormick)