* FTSEurofirst 300 up 0.5 pct
* Publicis, Actelion, Sky, ARM up over 4 pct after results
* Credit Suisse shares fall, brokers cite capital concerns
* Worries about ECB help hit shares in Athens
* Additional inflows on horizon from investors -fund mngr
By Lionel Laurent and Francesco Canepa
LONDON, April 21 (Reuters) - A raft of positive company earnings updates pushed European stock markets higher on Tuesday, with the Greek market a notable outlier as worries mounted about its banking sector.
Publicis, Sky, ARM Holdings were all up more than 4 percent after reporting results.
European companies are heading for their best earnings season in four years, sharply outperforming their U.S. counterparts on the back of a weak euro and improving economic conditions driven by the European Central Bank's bond-buying stimulus plan.
"We will see a further run-up in markets...We are seeing additional inflows from institutional clients," said Ingo Speich, portfolio manager at Union Investment in Frankfurt.
The pan-European FTSEurofirst 300 index was up 0.5 percent at 1,628.12 points, near multi-year peaks but off its earlier high as concerns about Greece capped sentiment.
The Athens ATG index fell 3.2 percent and hit its lowest since September 2012 after a Bloomberg report suggested the ECB had prepared a proposal to increase the haircut on the security that Greek banks offer in return for emergency liquidity.
The Greek banking index fell 6.6 percent.
Shares in Credit Suisse fell 2.8 percent despite better than expected first-quarter earnings. While the stock has gained some 44 percent since mid-January, some brokers raised concerns over the bank's capital strength.
"The issue today will be capital for a bank where concerns linger," said Omar Fall, analyst at Jefferies.
A weak euro helped Publicis report forecast-beating organic sales growth in the first quarter, while Actelion, Europe's biggest biotech firm, raised its full-year guidance after strong sales of its new heart and lung drug helped profits beat expectations.
Associated British Foods, however, fell 4.1 percent after it edged down its full-year earnings guidance on foreign currency concerns, prompting its shares to fall more than 2 percent.
Europe bourses in 2015: link.reuters.com/pap87v
Asset performance in 2015: link.reuters.com/gap87v
Today's European research round-up
Editing by Raissa Kasolowsky