* World stocks up for 4th day on growth optimism
* Euro gains
* Italian bond auction
By Dominic Lau
LONDON, June 11 (Reuters) - World equities extended their relief rally into a fourth day on Friday on optimism over global economic growth, while the euro rose and was on track to post its biggest weekly gain this year.
Copper also rose for the fourth day in a row, though crude slipped to trade below $75 a barrel.
After Belgium, Portugal and Spain found good demand for their bonds this week, Italy carried out a successful sale on Friday, easing immediate concerns about funding problems on the euro zone periphery and boosting appetite for the euro <EUR=>, banking shares and battered Spanish stocks in particular.
Investors were also optimistic about China's growth, even though fresh data showed inflation in the world's third-largest economy quickened to a 19-month high in May while its factory output and capital spending moderated. [
]On Thursday, Beijing announced a sharp jump in May exports, boosting investors' confidence about its economy's strength as Europe grapples with a sovereign debt problem.
"The flight to safety that we have seen out of euro and out of many euro bonds into gilts and into U.S. Treasuries suggests to me there is not a lot of value in bonds," said Neil Dwane, chief investment officer at Allianz's RCM.
"When people have maybe seen some of these rather fat tail events settle down again, they could well come back to equities market because the market looks very attractive."
World stocks measured by the MSCI All-Country World Index <.MIWD00000PUS> advanced 0.6 percent, helped by a 1.7-percent rise in Tokyo's Nikkei average <
>.The World Index has gained 1.6 percent this week but is still down 7.6 percent this year.
The pan-European FTSEurofirst 300 <
> put on 0.6 percent, with oil major BP <BP.L> recovering 7.3 percent amid an oil spill in the Gulf of Mexico, and the Thomson Reuters Peripheral Eurozone Countries Index <.TRXFLDPIPU> added 2.4 percent.U.S. stock index futures <SPc2> <DJc2> <NDc2> were flat to 0.2 percent higher, indicating a firmer start for Wall Street.
EURO STEADY
The euro <EUR=> was up 0.2 percent at $1.213X, extending a rebound to the fourth day. The single-currency is up 1.6 percent this week, on track for its best weekly gains this year.
"Euro/dollar is approaching an important level at $1.2150 -- above that point could see the ongoing correction extend to the upside," said Dag Muller, technical analyst at SEB in Stockholm. "Should we fail to take it out, the market could start to sell, and we can easily get back to those lows."
The euro fell to a more than four-year low earlier this week.
German government bond prices fell for a third successive day on Friday as investors bought 7 billion euros of newly issued Italian debt in a week that saw strong demand for fringe euro zone paper.
The two-year Schatz yield <DE2YT=TWEB> eased 0.9 basis points to 0.510 percent, while the 10-year Bund yielded <DE10YT=TWEB> 2.628 percent, up 1 basis point.
Crude <CLc1> eased 0.8 percent to trade below $75 a barrel, though copper <MCU3> rose 1.5 percent. (Additional reporting by Ian Chua, Joanne Frearson and Naomi Tajitsu; editing by Ron Askew)