* FTSEurofirst 300, STOXX Europe 600 down 0.2 pct
* STOXX 600 extends longest monthly streak since 1997
* Weak U.S. business activity data triggers profit taking
* ECB rate to boost shares - JPM AM
By Francesco Canepa
LONDON, April 30 (Reuters) - European shares slipped on Tuesday following some poor U.S. economic data but still ended the month in positive territory for the longest monthly winning streak since 1997.
April was the 11th straight monthly gain for the broad STOXX Europe 600 index. It ended the day down 0.2 percent at 296.72 points, edging off a 4-1/2 year high hit during the day.
The FTSEurofirst 300 index of pan-European shares fell 0.2 percent to 1,200.60 points.
Data showed business activity in the U.S. Midwest unexpectedly shrank to its lowest level since September 2009, denting investor sentiment because of its implications for global economic growth.
"It was another pretty bad set of data and it just feels the market is just struggling on volumes and impetus," Andy Ash, head of sales at Monument Securities, said. "People are considering how strong the market has been."
He suggested that if the market started to pull back from its recent gains, losses could be more than 5 percent.
Banking stocks helped curb losses on equity indexes after UBS and Deutsche Bank reported better first-quarter results than anticipated.
Their shares rose 5.7 percent and 6.1 percent in volume roughly four times their 90-day average.
Economic data from the euro zone published on Tuesday was weak and traders said European equities may need more dovish messages from the U.S. Federal Reserve and the European Central Bank later this week if stocks are to keep up the rally.
Inflation in the euro zone has fallen to a three-year low and unemployment has hit a new record, cementing expectations of an interest rate cut by the ECB on Thursday.
"I still think markets would go up if we did see a rate cut and we've seen some weak economic data to justify that," said Tom Elliot, global market strategist at JPMorgan Asset Management, who attached a 50 percent chance to a rate cut.
He had a positive view on European shares over the next six months, saying the asset class should continue to attract investors looking for higher yield than safe government bonds.
The STOXX 600 offers a 3.6 percent dividend yield on its 2013 earnings, compared with a 1.2 percent yield on Germany's 10-year government bond, Thomson Reuters data showed.