MFG Mizuho Financial Group Inc

TOKYO—Japan's biggest bank delivered a fresh message of frustration over negative interest rates to the Bank of Japan on Wednesday, saying it might stop acting as a primary dealer of Japanese government bonds.

Bank of Tokyo-Mitsubishi UFJ, the banking unit of Mitsubishi UFJ Financial Group Inc., would become the first Japanese bank to relinquish that role in the JGB market, which comes with privileges and obligations.

The possible action underscores Japanese lenders' rising tensions with the central bank over negative rates. The banks say negative rates haven't created more demand for loans but have hit their stock prices and threaten to cut their profits.

Banks are growing concerned that the BOJ, which in February set a rate of minus 0.1% on some commercial-bank reserves, might push the rate even lower. Banking executives, who say they suspect the BOJ might be willing to cut the rate to as low as minus 0.3%, are pressing central bank officials not to do so.

MUFG President Nobuyuki Hirano in April became the first top Japanese banking executive to publicly criticize the BOJ's negative-rate policy, saying it had actually caused households and businesses to rein in spending by creating a sense of uncertainty about the future.

"For the banking industry, the consequences, at least in the short term, are clearly negative," Mr. Hirano said in a speech in Tokyo.

A person close to the BOJ said Wednesday that a withdrawal by BTMU as a primary dealer would be "rather welcome news for us" because it would mean the bank is diversifying into riskier assets. It is unusual for investors such as banks to serve as dealers in other countries, including the U.S., where securities firms generally occupy that role, the person said.

BTMU's threatened action wouldn't have a big impact on the market in the short term. There are 22 banks and brokerages listed as primary dealers, a role that comes with entitlements such as meetings with Ministry of Finance officials.

Such a move might help limit the bank's exposure to JGBs if the BOJ's extraordinary monetary policies lead to market instability. Primary dealers are required to bid on at least 4% of each planned JGB issuance, a responsibility that banks may find increasingly unattractive as the BOJ's quantitative easing enters its third full year.

The BOJ has been buying ¥ 80 trillion ($747 billion) of JGBs annually, roughly equivalent to all new issuance, and now owns about third of the outstanding market. Its JGB purchases, and the introduction of negative rates, are meant to drive interest rates lower across the yield curve, creating demand for loans and pushing investors into higher-yielding "risk assets" as part of efforts to fuel economic growth.

The lower yields also help the Japanese government, which is relying on the central bank to absorb enough bonds to finance its deficits. The government is likely to propose an economic-stimulus plan valued at about ¥ 10 trillion ($93 billion) this fall, an aide to Prime Minister Shinzo Abe said Wednesday.

Since the central bank introduced negative rates, the yields on all JGBs with maturities of up to 10 years have been negative. Some analysts say the central bank's JGB purchases are distorting the market, and a withdrawal could result in a painful JGB selloff.

The benchmark 10-year JGB yield was little changed Wednesday at minus 0.120%.

"While the short-term impact [of a withdrawal by BTMU] is likely to be limited, the BOJ's overly easy monetary policy could lead to the instability in the JGB market in the long term," Deutsche Securities strategist Makoto Yamashita said.

In recent years, Japanese banks have aggressively shed exposure to JGBs. The top three have cut their holdings by about 20% over the past year. BTMU now has ¥ 22 trillion, while the banking units of Mizuho Financial Group Inc. and Sumitomo Mitsui Financial Group Inc. hold about ¥ 16 trillion and ¥ 10 trillion, respectively. Lenders are reluctant to hold negative-yielding bonds and are seeking higher yields elsewhere.

Mizuho and SMFG said they weren't considering relinquishing their status as primary dealers. Two affiliates of BTMU, Mitsubishi UFJ Morgan Stanley Securities and Morgan Stanley MUFG Securities, said they would remain primary dealers so their group could continue selling JGBs to investors.

Takashi Nakamichi and Megumi Fujikawa contributed to this article.

Write to Atsuko Fukase at atsuko.fukase@wsj.com

(END) Dow Jones Newswires

June 08, 2016 09:05 ET (13:05 GMT)

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