* Japan's Nikkei posts biggest one-day gain in 7 years
* Apple up marginally ahead of annual product launch event
* Barnes & Noble falls after sales fall for 5th straight quarter
* Indexes up: Dow 0.24 pct, S&P 0.24 pct, Nasdaq 0.20 pct (Adds details, changes comment, updates prices)
By Tanya Agrawal
Sept 9 (Reuters) - Wall Street trimmed early gains and was little changed in late morning trading on Wednesday as the rally fueled by hopes of further stimulus measures in China faded.
China's Ministry of Finance said on Wednesday the government will strengthen fiscal policy, boost infrastructure spending and speed up reform of its tax system, adding to other steps to reenergize sputtering growth.
The Shanghai Composite closed 2.3 percent higher on Wednesday. Adding to the positive sentiment, Japan's Nikkei 225 rose 7.7 percent, its biggest one-day rise since the global financial crisis, as Prime Minister Shinzo Abe signaled a cut in corporate taxes.
"What's causing us to trade lower isn't anything fundamental and is more technical," said Ryan Larson, head of U.S. equity trading at RBC Global Asset Management in Chicago.
"The volume has also been a little bit lighter which is indicative of more short covering than ... actual buying."
At 11:17 a.m. ET (1517 GMT), the Dow Jones industrial average was up 38.89 points, or 0.24 percent, at 16,531.57, the S&P 500 was up 4.82 points, or 0.24 percent, at 1,974.23 and the Nasdaq Composite was up 9.49 points, or 0.2 percent, at 4,821.42.
Seven of the 10 major S&P sectors were higher with the materials index's 0.73 percent rise leading the advancers.
U.S. stocks rose more than 2 percent on Tuesday, bouncing after steep losses last week.
U.S. job openings surged to 5.753 million in July from 5.323 million in June, Labor Department data showed, suggesting strength in the economy ahead of the U.S. Federal Reserve's interest rate meeting next week.
"While there is nothing specific causing the pullback, trading is expected to be a bit range-bound till the Fed meeting," said Brian Fenske, head of sales trading at ITG in New York.
Apple shares were up marginally at $112.48. The iPhone maker is expected to unveil new offerings at its annual conference later on Wednesday.
Barnes & Noble fell 15.9 percent to $13.70 after the largest U.S. bookstore chain reported a decline in sales for the fifth consecutive quarter.
Tetraphase Pharmaceuticals sank 78 percent to $9.77 after its experimental bowel drug failed to meet the main goal in a late-stage study.
Dave & Buster's Entertainment jumped 8.6 percent to $40.56 after the restaurant and arcade chain operator raised its 2015 revenue and comparable store sales forecasts.
Advancing issues outnumbered decliners on the NYSE by 1,569 to 1,282. On the Nasdaq, 1,346 issues rose and 1,281 fell.
The S&P 500 index showed 3 new 52-week highs and no new lows, while the Nasdaq recorded 31 new highs and 21 new lows. (Reporting by Tanya Agrawal; Editing by Don Sebastian and Saumyadeb Chakrabarty)