* Stocks rally on big lift in 2nd quarter GDP revision.
* Oil falls on IEA supply plan if Gustav slams U.S. Gulf
* Financial, retail stocks lead rally
* Dow up 1.6 pct, S&P 500 up 1.1 pct, Nasdaq up 1.0 pct (Updates to midday, changes byline)
By Richard Leong
NEW YORK, Aug 28 (Reuters) - U.S. stocks rallied on Thursday as a surprisingly big upward revision to U.S. growth in the second quarter and lower oil prices fanned optimism about the economy.
The government's report of second-quarter growth of 3.3 percent, fueled by exports and consumer spending, spurred buying of industrial shares such as Caterpillar <CAT.N>, often described as an economic bellwether, and retailers.
The improved economic view, together with positive news in the financial sector also sparked investors to scoop up financial stocks like MBIA Inc <MBI.N>.
"You hate to be underweight in stocks when you have an economy that is performing better-than-expected," said James Paulsen, chief investment officer at Wells Capital Management in Minneapolis.
The 3.3 percent growth rate in the second quarter topped the government's initial estimate of growth of 1.9 percent. [
].The Dow Jones industrial average <
> was up 187.19 points, or 1.63 percent, at 11,689.70. The Standard & Poor's 500 Index <.SPX> was up 13.78 points, or 1.08 percent, at 1,295.44. The Nasdaq Composite Index < > was up 24.35 points, or 1.02 percent, at 2,406.81.A late morning retreat in the price of oil sparked a fresh round of buying, easing fears about constraints on spending, and sent the major stock indexes to session highs.
U.S. crude futures <CLc1>, which initially had jumped above $120 a barrel, turned negative after the International Energy Agency pledged to help with additional supply if Tropical Storm Gustav damages oil and natural gas facilities in the Gulf of Mexico. For details, see [
].FINANCIALS LEAD
Financial shares powered the day's rally amid optimism about mortgage finance companies Fannie Mae <FNM.N> and Freddie Mac <FRE.N> after Fannie reshuffled its top management in a move to better implement a plan to preserve capital and cut losses.
The management shake-up "shows that Fannie Mae is trying to get the ship moved in the right direction," said Arthur Hogan, chief market analyst at Jefferies & Co. in Boston.
On Thursday, Lehman Brothers said Fannie's capital and reserves positions are better than market perceptions, adding that it may not need more externally raised capital. [
]Fannie shares rose 7.4 percent to $6.99. Freddie shares rose 10.1 percent to $5.25.
Also helping financial services companies, bond insurer MBIA Inc said late on Wednesday that it plans to reinsure a $184 billion portfolio of investment-grade U.S. public finance credits.
MBIA was the day's biggest percentage winner among Big Board stocks, with its shares jumping 25 percent to $15.01.
A gauge on financial shares <.GSPF> soared 3.12 percent.
Shares beyond the financial sector also participated in the rally.
Upscale U.S. jeweler Tiffany & Co <TIF.N> shares rose 8.7 percent to $43.14 after it posted a higher-than-expected profit and raised its full-year forecast on strong sales overseas.
Shares of heavy equipment maker Caterpillar <CAT.N> gained 2.6 percent at $71.38 on the improved economic backdrop and remarks from its chief executive, Jim Owens, who said its business in China could double by 2010.
The slide in oil, which had risen the past three sessions, hurt energy shares. A index on energy companies <.GSPE> was down 1.8 percent.
The government on Thursday also reported that the number of U.S. workers filing new claims for jobless benefits fell to a level that was a touch lower-than-expected. (Additional reporting by Kristina Cooke; Editing by Leslie Adler)