(Corrects to show Markit flash U.S. PMI to be released at 9:45 a.m. EDT, not 9:00 a.m.)
* Flash PMI, existing home sales data due
* Wisconsin Energy to buy Integrys for $9.1 bln
* Futures: Dow off 4 pts, S&P up 0.25 pt, Nasdaq off 2.25
By Chuck Mikolajczak
NEW YORK, June 23 (Reuters) - U.S. stock index futures were little changed on Monday, after a six-day rally in the benchmark S&P 500, as upbeat manufacturing data in China was offset by soft readings on business activity in Europe.
* The HSBC/Markit Flash China Manufacturing Purchasing Managers' Index rose to 50.8 in June from May's final reading of 49.4, topping the 49.7 and edging above the 50-point level that separates growth in activity from contraction for the first time since December.
* But Markit's Composite Purchasing Managers' Index (PMI), for the euro zone, fell to 52.8 from May's 53.5, well below the estimate for 53.5 in a Reuters survey, with France being a notable laggard showing contraction.
* The S&P 500 has risen for six straight sessions, its longest streak since mid-April, to gain 1.7 percent over that span.
* Markit's flash PMI reading for the U.S. for June is due out at 9:45 a.m. EDT (1345 GMT). Expectations call for a reading of 56.5 for the month, just above the prior 56.4.
* Later in the session at 10:00 a.m. (1400 GMT). Existing home sales data for May is due, with expectations for a rise to an annual rate of 4.73 million units from 4.65 million in April.
* S&P 500 e-mini futures were up 0.25 point and fair value - a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract - indicated a flat open. Dow Jones industrial average e-mini futures fell 4 points and Nasdaq 100 e-mini futures lost 2.25 points.
* 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.
* 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 were up 16.3 percent to $70.90 in light premarket trading.
* European stocks dipped on the downbeat readings of euro zone business while Asian stocks rose on encouraging data from China's factory sector. (Editing by Bernadette Baum)