* U.S. Flash PMI, existing home sales top expectations
* Wisconsin Energy to buy Integrys for $9.1 bln
* Oracle to buy Micros for $68 per share
* Dow off 0.14 pct, S&P off 0.02 pct, Nasdaq off 0.05 pct (Updates to open, adds U.S. PMI, housing data, comments)
NEW YORK, June 23 (Reuters) - U.S. stocks were little changed on Monday following a six-day rally in the benchmark S&P 500 and a mixed bag of global economic data.
Financial data firm Markit said its preliminary, or "flash," U.S. Manufacturing Purchasing Managers Index rose to 57.5 in June, above economist expectations for 56.5 and the highest reading since May 2010.
Housing data was also encouraging. The National Association of Realtors said existing home sales in May increased 4.9 percent to an annual rate of 4.89 million units, the largest increase since August 2011. The PHLX housing sector index gained 1.2 percent.
Earlier, the HSBC/Markit Flash China Manufacturing Purchasing Managers' Index rose into expansion territory for the first time in six months with a 50.8 reading for June, from May's final reading of 49.4, beating the 49.7 forecast in a Reuters poll of economists.
But Markit's Composite Purchasing Managers' Index (PMI) for the euro zone fell to 52.8 from May's 53.5, well below the 53.5 estimate, with France being a notable laggard and showing contraction.
"Between the positive narrative provided by the Chinese expansion in manufacturing and the EU's continued struggles with continuing the very fragile expansion intact, U.S. markets are left in what appears to be a bit of a balancing act and as a direct result we are flat," said Peter Kenny, chief executive of Clearpool Group in New York.
The S&P 500 had risen for six straight days heading into Monday's trading, gaining 1.7 percent over that span in its longest streak of advances since mid-April.
The Dow Jones industrial average fell 22.94 points, or 0.14 percent, to 16,924.14, the S&P 500 lost 0.41 points or 0.02 percent, to 1,962.46 and the Nasdaq Composite dropped 2.07 points or 0.05 percent, to 4,365.96.
France won an option to buy 20 percent of Alstom from construction group Bouygues on Sunday in an eleventh-hour deal, clearing the way for the agreed sale of Alstom's energy business to General Electric. GE shares slipped 1 percent to $26.70.
Oracle Corp said it would buy Micros Systems in a $5.3 billion deal to expand its offerings in the hospitality and retail industries. Micros shares rose 3.3 percent to $67.96 while Oracle shares were up 1.2 percent to $41.29.
Wisconsin Energy said it would buy Integrys Energy Group Inc in a deal valued at $9.1 billion to create a larger, more diverse Midwest electric and natural gas delivery company. Integrys shares jumped 14.6 percent to $69.87. (Editing by Bernadette Baum)