* GDP reading below forecast relieves stimulus concerns
* S&P 500 above 1,600 for first time since last Thursday
* Adobe and Microsoft rise on analysts' upgrades
* Dow up 1.2 pct, S&P 500 up 1.2 pct, Nasdaq up 1 pct
By Alison Griswold
NEW YORK, June 26 (Reuters) - U.S. stocks climbed for a second straight day on Wednesday as a downward revision in the growth rate of gross domestic product soothed investors' concerns that the Federal Reserve would begin to withdraw its stimulus in the near future.
The economy grew at an annual rate of 1.8 percent in the first quarter, according to the Commerce Department's final estimate of gross domestic product. That was well below expectations for growth at a 2.4 percent annual rate.
The three major U.S. stock indexes surged at the open and extended gains in the afternoon, with the S&P 500 moving back above the key technical level of 1,600 for the first time since last Thursday.
The rally was broad, with all 10 industry sectors in the S&P 500 advancing. The healthcare, consumer discretionary and financial sectors ranked among the session's biggest gainers.
Paul Brigandi, senior vice president of trading at Direxion Funds in New York, said the market has viewed both strong and weak economic data as positive in the past two days.
"Yesterday we had some better-than-expected numbers and that led to a rally, and then today the GDP report showed slower-than-expected economic growth, and I think that led people to believe that the Fed will not be in a rush to reduce stimulus," he said.
While the GDP data looks backward and includes the start of cutbacks in federal spending, analysts said it could influence Fed considerations of whether the economy is strong enough for it to begin scaling back its $85 billion in monthly bond purchases.
Stocks have been closely tied to the central bank's easy money policy, with the Dow and the S&P 500 hitting a series of record closing highs as investors bet that the bond buying would remain in place, and then dropping dramatically on hints that the stimulus could be reduced before the end of the year.
The Dow Jones industrial average rose 170.41 points or 1.16 percent, to 14,930.72. The S&P 500 gained 18.23 points or 1.15 percent, to 1,606.26. The Nasdaq Composite added 34.29 points or 1.02 percent, to 3,382.18.
The S&P has gained 1.9 percent over the past two sessions, its best two-day rally in three weeks following a massive selloff. Last week, the S&P 500 index posted its worst week since April. The benchmark index remains 4 percent below its all-time closing high of 1,669.16 reached on May 21.
Tuesday's rally came after the People's Bank of China eased concerns about a possible banking crisis in the world's second-largest economy. Data on durable goods, new home sales and consumer confidence added to the positive tone.
Tech companies' shares advanced following bullish analyst commentary. Adobe Systems Inc rose 3.4 percent to $45.87 after Jefferies & Co upgraded the stock to "buy" from "hold," citing expectations for more new users, while Microsoft Corp climbed 2 percent to $34.36 after Morgan Stanley raised its rating on the software company's stock to "overweight" and increased its price target to $40.
On the downside, gold stocks slid as the precious metal fell to its lowest in almost three years, putting it on course for a record quarterly loss.
U.S.-listed shares of Gold Fields Ltd dropped 6.3 percent to $4.76 and Barrick Gold Corp fell 6.9 percent to $15. Newmont Mining was one of the S&P 500's biggest decliners, sliding 5.4 percent to $27.37.
Apollo Group, owner of the University of Phoenix, was the S&P 500's biggest decliner, tumbling 8.9 percent to $17.65 a day after reporting its third-quarter results.
As the end of the second quarter approaches, stocks may also get a boost from "window dressing," the practice of fund managers selling underperforming stocks and buying better- performing shares to enhance the appearance of their portfolios.