* Stocks rally globally on better-than-expected U.S. data
* Oil hits $74 a barrel as U.S. manufacturing data shines
* Government debt prices fall on signs of global growth
* China data also revives appetite for riskier assets (Updates with close of U.S. markets)
By Herbert Lash
NEW YORK, Sept 1 (Reuters) - Global stocks posted their biggest percentage gain this summer on Wednesday after U.S. and Chinese manufacturing data eased worries about the world's flagging economy and helped spur a rally in commodities.
The U.S. dollar and Japanese yen fell broadly after the release of the manufacturing data and on news that Australia's economy grew in the second quarter at its fastest pace in three years. For details see: [
]Oil rose more than 3 percent to above $74 a barrel and copper hit its highest level in more than four months after the upbeat economic news boosted sentiment that had been battered by a spate of recent poor U.S. economic data.
As investors' appetite for riskier assets rose, government debt prices fell sharply. Benchmark 10-year U.S. Treasury notes and German Bund futures shed more than a full point.
"A rebound in risk appetite lured wary investors out of the relative safety of U.S. dollar-denominated assets," said Omer Esiner, chief market analyst at Commonwealth Foreign Exchange in Washington. "Surging stocks and generally firmer commodities signaled an improving mood throughout global markets."
Major stock indexes around the world rallied more than 2 percent. MSCI's all-country world index <.MIWD00000PUS> surged 2.7 percent in its biggest one-day percentage gain since May 27.
European shares rose at their fastest pace in three months and Wall Street posted its best day in eight weeks, as the Nasdaq and S&P 500 stock gauges rose almost 3 percent.
U.S. stocks rallied in a broad-based advance after data showed U.S. factory activity grew faster than forecast in August and Chinese manufacturing rebounded last month.
More than six stocks rose for every one that fell among shares listed on the New York Stock Exchange. Economically sensitive sectors like industrials and basic materials posted the biggest gains among U.S. stocks.
Low volume helped exaggerate gains due to aggressive bidding by momentum players and hedge funds, according to Jason Weisberg, director of institutional trading at Seaport Securities in New York.
"They're moving the needle with force, but there's not a lot of volume behind it. There's a bunch of people trying to chase returns and this becomes a vicious game," Weisberg said.
Heavy equipment maker Caterpillar Inc <CAT.N>, which is sensitive to changes in economic activity, rose 4.6 percent to $68.16.
Energy-related shares rose with as the global economic data drove up the price of crude oil. The NYSE Arca Oil stock index <.XOI> rose 4.1 percent and the PHLX oil services index <.OSX> jumped 4.8 percent.
The global stock rally gained momentum after the Institute for Supply Management showed U.S. factory activity rose in August for a 13th straight month in a reading that was higher than the median forecast of economists surveyed by Reuters.
Investors had been expecting the ISM reading to show a decline in manufacturing from July, which would have fit with recent data that has depicted a slowdown in U.S. growth.
ISM said its index of U.S. factory activity rose to 56.3 in August from 55.5 in July, much higher than a survey of 79 economists by Reuters whose median forecast was 53.0.
Reduced fears of a further slide in global growth sent investors into perceived riskier currencies such as the euro and Australian dollar.
The euro climbed above $1.2850 at one point and the Australian currency soared 2 percent versus the U.S. dollar.
The euro <EUR=> was up 0.99 percent at $1.281, while against the yen, the U.S. dollar <JPY=> was up 0.33 percent at 84.44.
The greenback was down against a basket of major currencies, with the U.S. Dollar Index <.DXY> down 0.90 percent at 82.453.
"The acceleration in manufacturing activity in the U.S. and China alleviates some of the fears for a global slowdown and a double-dip recession in the U.S," said Kathy Lien, director of currency research at GFT in New York.
Benchmark U.S. crude oil futures for October <CLc1> settled $1.99 higher at $73.91 a barrel, after rising as high as $74.48.
London ICE Brent crude futures <LCOc1> rose $1.77 to end at $76.35.
The benchmark 10-year U.S. Treasury note <US10YT=RR> was down 30/32 in price to yield 2.58 percent.
Gold turned lower after an initial rally pushed prices to a two-month high above $1,250 an ounce, as the increased appetite for riskier assets such as stocks decreased bullion's appeal as an alternative investment. [
]U.S. gold futures for December delivery <GCZ0> settled down $2.20 an ounce to $1,248.10. (Reporting by Rodrigo Campos, Gene Ramos, Wanfeng Zhou, John Parry and Frank Tang in New York; Brian Gorman and Dominic Lau; Writing by Herbert Lash; Editing by Leslie Adler)