GLOBAL MARKETS-U.S., EU debt optimism buoy stocks, euro

* Hints of progress in U.S. debt talks, but doubts persist

* Euro rises again on hopes ahead of EU debt crisis summit

* Apple reports blockbuster sales, beats estimates

* Gold retreats from record high, below $1,600/oz (Updates market action; adds fresh quote)

By Richard Leong

NEW YORK, July 20 (Reuters) - World stocks, with the exception of Wall Street, rose on Wednesday on strong earnings results and hopes for an increase in the U.S. debt ceiling, while the euro gained on guarded optimism that an accord to avert a Greek default would be reached.

Gold retreated from a record high of $1,609.51 hit on Tuesday but was still toward the top of recent trading levels. It has been boosted by both the U.S. and European debt fears.

A group of U.S. lawmakers, dubbed the "Gang of Six," presented a new plan late on Tuesday that could revive stalled U.S. debt talks. This reduced fears that lawmakers may fail to lift the statutory $14.3 trillion federal borrowing limit and cause the world's biggest economy to default and to lose its top-notch credit grade from rating agencies. For more, please see:[ID:nN1E76H1Y0]

U.S. President Barack Obama expressed support for the bi-partisan proposal, but doubts remained whether it could muster enough votes to pass.

"I wouldn't jump for joy until I see the details," Komal Sri-Kumar, chief global strategist at Trust Company of the West in Los Angeles, which manages $121 billion in assets, said of the plan. "I would also like to see diligent spending control rather than just raising the debt ceiling."

In Europe, French ministers said European leaders were less divided than the media was reporting and were likely to reach an accord at a summit in Brussels on Thursday that will ease Greece's debt woes. [ID:nLDE76J0CA]

Although these developments provided a positive backdrop for stocks and growth-oriented investments, there are lingering doubts whether they go far enough to keep the U.S. and European debt problems from spiraling into a global crisis.

"There's still tremendous uncertainty around the U.S. debt ceiling and the euro-zone, and while earnings have been good, it isn't surprising to have a big up day followed by a down day," said David Carter, chief investment officer at Lenox Advisors in New York, referring to Tuesday's stocks gains.

In the meantime, encouraging company results provided a catalyst for investors to put cash into equities.

Apple Inc reported blockbuster quarterly results after the market closed on Tuesday. The maker of iPhone and iPad rose 3 percent to $387.44 a share.

U.S. stocks were moderately lower, losing steam a day after Wall Street posted its best day since March. But Apple's strong earnings helped put a floor under stock prices.

At 12:15 p.m. EDT (1615 GMT), the Dow Jones industrial average <.DJI> was down 17.71 points, or 0.14 percent, at 12,569.71. The Standard & Poor's 500 Index <.SPX> was down 0.80 points, or 0.06 percent, at 1,325.93. The Nasdaq Composite Index <.IXIC> was down 14.78 points, or 0.52 percent, at 2,811.74.

In Europe, the FTSEurofirst 300 <.FTEU3> gained around 1.2 percent, cutting its year-to-date losses to around 3 percent.

Earlier, Japanese stocks marked their biggest daily rise in three weeks. The Nikkei <.N225> closed up 1.2 percent.

World stocks as measured by MSCI <.MIDW00000PUS> clung to a 0.6 percent gain despite losses in U.S. stocks.

More risk appetite reduced the appeal of bonds. U.S. Treasuries fell, with the 30-year bond off 12/32 in price to yield 4.24 percent and the benchmark 10-year U.S. Treasury note down 12/32 with its yield at 2.92 percent.

In the currency market, the euro traded at $1.4196, having risen around 0.6 percent on the day to a session high of $1.4239. For more, see [FRX/]

Data signaling strong energy demand, together with improved investor sentiment, helped lift oil prices. Brent oil futures in London were up $1.07 at $118.10 a barrel, while U.S. crude for August delivery in New York rose 76 cents to $98.26. For more, see [O/R] (Additional reporting by Ryan Vlastelica and Nick Olivari in New York; Jessica Mortimer and Jan Harvey in London; Editing by Dan Grebler)