TOKYO: US financial giant Morgan Stanley plans to keep control of part of its brokerage operation in Japan, revising a merger plan with Mitsubishi UFJ Financial Group (MUFG), news reports said Wednesday.

The two firms announced in March they would fully merge their securities firms in Asia's biggest economy, with MUFG taking a 60-percent stake in the new unit and Morgan Stanley holding the remaining 40 percent.

But two firms have agreed to revise the deal, allowing Morgan Stanley to keep some operations, including stock dealing for corporate clients, the Nikkei business daily reported without revealing its sources.

Due to the revision, the merger will be delayed by about two months, to May 2010, the daily said.

The deal was part of their broader alliance after MUFG, Japan's biggest bank, threw Morgan Stanley a nine-billion-dollar lifeline last year in the midst of the global financial crisis.

An MFUG spokesman declined to confirm the change, which the Japanese bank was reportedly set to announce alongside its earnings results later Wednesday.