* Banks push up index after Barclays unveils share issue
* Firm crude boosts oils; miners track metal prices lower
* FTSE 100 rises 0.4 pct ahead of Fed
By Rebekah Curtis
LONDON, June 25 (Reuters) - The British blue-chip index rose by midday on Wednesday, with Barclays <BARC.L> leading banking stocks higher after unveiling a 4.5 billion pound share issue, while firm crude prices helped oil shares.
By 1121 GMT the FTSE 100 <
> was up 23.3 points, or 0.4 percent, at 5,657.2, bouncing into the black after falling 0.6 in the previous session.But investors remained cautious ahead of an interest rate decision by the U.S. Federal Reserve late on Wednesday. The Fed is widely expected to keep borrowing costs unchanged at 2 percent when it announces its June rate verdict at 1815 GMT.
"It's not so much the decision that has been awaited, but more important would be the tone of the accompanying words, and those words would be scrutinised," said Richard Hunter, head of UK equities at Hargreaves Lansdown.
"With that in mind, there is an element of the UK market treading water. In the short term, we are bound to see much more volatility. There are going to be some difficulties coming along and more cautious investors are waiting on the sidelines with their cash potentially to buy into weakness on specific stocks."
Analysts said the market will scour the Fed's statement to see whether the central bank will signal more concern about inflation or downside risks to the U.S. economy.
Banks topped the index, with Barclays <BARC.L> jumping more than 6 percent after announcing the raising of new funds through the issue of 1,576 million new shares. By 1124 GMT, almost 85 million shares had changed hands, more than the 30-day full-day average of 75.7 million. [
]"It's a fairly chunky amount ... They'll find plenty of willing buyers," Peter Dixon, an economist at Commerzbank, said.
"But those who delay their efforts to raise capital in this way, especially if they haven't got such a big name, may well be struggling," he said.
Other banks also gained, with HBOS <HBOS.L> rising 5.5 percent, Royal Bank of Scotland <RBS.L> adding 4.5 percent and Standard Chartered <STAN.L> up 3.8 percent.
The sector has been the worst hit by a credit market crisis stemming from the collapse of risky U.S. mortgages. Banks have been forced to raise fresh capital after taking huge writedowns.
OILS POWER ON
Oil stocks gained as U.S. crude prices traded just shy of $137 a barrel, approaching a record high of around $140. BP <BP.L> added 2.1 percent, Royal Dutch Shell <RDSa.L> rose 0.8 percent and BG Group <BG.L> gained nearly 1 percent.
SABMiller <SAB.L> shares added 0.8 percent after sources familiar with the situation said the brewer has held informal discussions with Grupo Modelo <GMODELOC.MX> and InBev NV <INTB.BR> to explore options including a merger of Modelo and SABMiller. [
]Pub owner Punch Taverns Plc <PUB.L> jumped 2.7 percent after saying it was confident of meeting market full-year profit forecasts and its balance sheet remained strong. [
]But mining stocks suffered and were the biggest loser on the index, as metal prices softened. BHP Billiton <BLT.L>, Anglo American <AAL.L>, Vedanta Resources <VED.L>, Xstrata <XTA.L> and Antofagasta <ANTO.L> all fell between 0.6 and 4.0 percent.
United Utilities <UU.L> lost 4.6 percent, while Compass Group <CPG.L> and Experian <EXPN.L> also fell, after they all went ex-dividend.
Old Mutual <OML.L> dropped 3.5 percent after saying operating profits at its U.S. asset management and life businesses are running below 2007 levels as a result of tougher markets.
(Editing by Erica Billingham)