* MSCI world equity index steady at 304.60
* Corporate optimism eclipses euro zone banking concerns
* Oil down; euro firms on Stark's ECB measures comments
By Natsuko Waki
LONDON, Sept 28 (Reuters) - World stocks held steady on Tuesday as euro zone banking concerns offset optimism on the corporate sector, while the euro rose after a European Central Bank official pointed to the withdrawal of support measures next year.
The premium investors demand to hold Irish or Portuguese government bonds hit euro lifetime highs after Standard & Poor's warned it may cut Ireland's credit rating if the country poured more than 35 billion euros into Anglo Irish Bank
Concerns about euro zone banks and some countries' debts have prompted investors to take profits on risky assets after optimism from increased corporate M&A activity pushed world stocks to near five-month highs on Monday.
"Markets look a bit tired and are looking to economic data to help them break higher. There are tentative signs that the rate of slowing in the global economy is running its course but markets are still nervous about that," said Bernard McAlinden investment strategist at NCB Stockbrokers in Dublin.
"In Europe you have got worries about the banking system in the peripheral euro zone economies flaring up again and in general there are worries about the strength of the global economy." MSCI world equity index and the Thomson Reuters global stock index erased earlier losses to stand steady on the day.
The FTSEurofirst 300 index was broadly unchanged on the day. Emerging stocks fell 0.3 percent while U.S. stock futures pointed to a firmer open on Wall Street.
U.S. crude oil fell 0.6 percent to $76.04 a barrel.
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German Bund futures fell 9 ticks. The 10-year Irish/German government bond yield spread widened by five basis points to 456 bps, while Portugal's grew 22 bps to 446 bps.
"Everyone is looking for where the next contagion among the peripherals will come from after Greece," Charles Morris, head of absolute return at HSBC Global Asset Management, said.
"We are taking a risk-free approach and will not buy peripherals at all unless they go formally distressed when they become interesting again. We have a large cash position and if we are buying anything it is one-to-two year German debt."
The euro rose 0.3 percent to $1.3486 after European Central Bank executive board member Juergen Stark said the central bank will not renew some of its support measures when they mature at the end of the year.
The bank, where Stark is seen as an inflation "hawk", is expected to decide at its December meeting whether to call time on more of the emergency support for banking liquidity put in place during the financial crisis.
The dollar fell 0.1 percent against a basket of major currencies, erasing gains made after the Wall Street Journal reported the Fed was considering buying a much smaller amount of bonds for a brief period and decide whether to do more depending on how the economy fared.
(Additional reporting by Harpreet Bhal; editing by Patrick Graham)