* News of Nomura share sale batters financials
* Commodities fall hits trading firms
* JAL tumbles as woes continue
By Elaine Lies
TOKYO, Sept 25 (Reuters) - Japan's Nikkei stock average slid 2.9 percent on Friday, as financial shares were hit hard after Nomura Holdings said it plans to issue up to $5.6 billion in shares, raising fears other banks could follow suit.
Nomura shares were untraded due to a glut of sell orders after the announcement by Japan's largest broker, with investors appearing to focus on the negative technical impact of the step on Nomura's shares instead of the positive implications for the company's business operations.
But losses were broad-based, with trading houses hit by falling commodity prices and exporters hit as the yen advanced against the dollar.
"Today's fall (in financial stocks) is largely because Nomura suddenly announced that it would raise new capital," said Soichiro Monji, chief strategist at Daiwa SB Investments.
"While the overall market is down, that's what's behind the additional fall in financial stocks."
Analysts say Nomura's offering, which would boost the number of its outstanding shares by about 30 percent, could signal another round of fundraising by Japanese banks in the face of a global regulatory push for banks to carry bigger capital buffers to prevent another crisis.
The G20 grouping of rich and developing countries, currently meeting in Pittsburgh, has been pushing for global banks to boost their capital, in particular calling for issues of common shares. The benchmark Nikkei lost 305.17 points to 10,239.05, while the broader Topix fell 3.1 percent to 920.65.
The Nomura news hit a sector already made jittery by a string of events, including financial services minister Shizuka Kamei's interest in introducing a moratorium on the repayment of the principal on mortgages and bank loans to help small and midsize businesses.
"There's a lot of concerns about the financial system here right now, and the general atmosphere isn't so good," said Noritsugu Hirakawa, a strategist at Okasan Securities.
An overnight fall on Wall Street, fed by worries that authorities might be curbing stimulus measures too soon, saw the S&P 500 hit by its worst two-day drop in three weeks and also weighed on sentiment.
World central banks said they would scale back infusions of U.S. dollars into their banking systems, fuelling unease triggered a day earlier when stocks sold off following the U.S. Federal Reserve's decision to slow purchases of mortgage debt -- a key pillar of its efforts to support mortgage lending.
But Japanese market players said the impact was limited.
"We need to see actual figures before this will really matter. Just a statement itself means little," said Tomomi Yamashita, a fund manager at Shinkin Asset Management.
FINANCIALS FALTER
Nomura was untraded, with its price indicated at 573 yen -- down 15.9 percent from Thursday's close -- after announcing the share sale, its second since it bought the European and Asian operations of Lehman Brothers, targeting investments and tighter capital requirements.
"Given that this is their second large-scale share sale this year, serious concerns about dilution are inevitable," said Okasan's Hirakawa.
Mitsubishi UFJ Financial Group lost 6.1 percent to 495 yen, while Sumitomo Mitsui Financial Group fell 5.2 percent to 3,130 yen. Mizuho Financial Group lost 4.9 percent to 175 yen.
The securities subindex tumbled 10.8 percent, becoming the biggest loser among the subindexes, while the banking subindex lost 4.5 percent.
Japan Airlines was battered after it pleaded on Thursday for a government bailout, though the new transport minister held back his support on concerns the carrier's cost-cutting plans would not be enough.
The transport ministry said on Friday it has launched a special team to draw up restructuring plans for JAL by the end of November after the struggling carrier's own plans failed to satisfy government officials.
JAL shares lost 5.6 percent to 136 yen.
Trading houses tumbled after copper fell to a one-month low in New York on Thursday and oil fell 4.5 percent.
Itochu Corp lost 5.6 percent to 627 yen and Mitsubishi Corp fell 3.7 percent to 1,891 yen.
Trade was active on the Tokyo exchange's first section, with 995 million shares changing hands, above last week's morning average of 909 million.
Declining stocks outnumbered advancing ones by more than 11 to 1. (Additional reporting by Tokyo newsroom; Editing by Joseph Radford)