Hedge fund Okumus Capital is a step closer to finding out who was buying shares of

Mercury Interactive

(MERQ)

just days before a big merger announcement.

A New York state judge has given the $800 million hedge fund the green light to seek information from

Goldman Sachs

(GS) - Get Report

and

Jefferies

(JEF) - Get Report

about the identities of any customers who bought some 2.4 million shares of Mercury from Okumus Capital in late July.

Last month Okumus

went to court seeking that information, after claiming that some of the buyers may have been improperly tipped off that

Hewlett-Packard

(HPQ) - Get Report

was about to announce a $4.5 billion acquisition of Mercury.

The hedge fund claims it lost $27 million by selling Mercury shares ahead of the announcement.

A state judge approved the unusual request last week, after neither Goldman Sachs nor Jefferies appeared in court to challenge the demand. Officials with Goldman Sachs and Jefferies were not available for comment.

It's possible, however, that Goldman Sachs and Jefferies may still challenge the demand for customer information.

The investment firms could be waiting for lawyers for Okumus to formally serve a subpoena on them. Legal experts say once that occurs, the investment firms could go to court seeking to quash -- or kill -- the subpoena.

To date, Okumus has not made any of wrongdoing by either Goldman Sachs or Jefferies.

But the unstated implication in the hedge fund's legal filing is that someone tipped off customers and others on Wall Street about the deal, making Okumus Capital an unwitting seller.

Goldman Sachs served as the main adviser to Mercury Interactive in the transaction.