* FTSEurofirst 300 up 1.3 pct, reverses Tuesday's loss
* Marks & Spencer jumps after results
* Two-thirds of companies meet or beat forecasts -data
* Bilfinger slumps after latest profit warning
* Lack of new ECB measures could hit market rally -traders
By Blaise Robinson and Sudip Kar-Gupta
PARIS/LONDON, Nov 5 (Reuters) - European stocks rebounded on Wednesday, helped by positive company results including from British retailer Marks & Spencer, whose shares surged more than 8 percent.
Some traders said the rally could be short-lived if European Central Bank (ECB) chief Mario Draghi fails on Thursday to unveil new stimulus measures to spur economic growth in the struggling euro zone.
"If we get nothing from the ECB, which is a close call, we may see some downside," Philippe Gijsels, chief strategy officer at Fortis Bank, told Reuters Insider Television. (reut.rs/1vHB5Og)
Marks & Spencer jumped 8.5 percent after posting a rise in underlying first-half profit for the first time in four years, beating expectations, while German chemicals distributor Brenntag gained 4.9 percent, boosted by forecast-beating earnings.
German reinsurer Hannover Re gained 1.7 percent after its net profit beat forecasts, while Italian asset manager Azimut rose 3.5 percent after posting net in-flows in October.
Bucking the trend was Finnish stainless steel maker Outokumpu which slumped 10 percent after reporting a bigger-than-expected quarterly loss.
German industrial services and building group Bilfinger SE also lost around a tenth of its stock market value after issuing its fourth profit warning since the end of June.
About halfway into Europe's earnings season, 64 percent of companies have managed to meet or beat profit forecasts, while 59 percent have met or beaten revenue forecasts, according to Thomson Reuters StarMine data.
In absolute terms, profits are up 13 percent versus the same quarter a year ago, while revenues are down 0.2 percent, highlighting the fact that Europe's earnings rebound has mostly come from cost-cutting and lower financing costs.
The pan-European FTSEurofirst 300 blue-chip index was up by 1.3 percent at 1,344.32 points going into the close of the trading session, while the euro zone's blue-chip Euro STOXX 50 index rose 1.6 percent to 3,081.25 points.
The FTSEurofirst fell 1 percent on Tuesday after Reuters reported that euro zone central bankers plan to challenge ECB chief Draghi over what they consider his secretive management style.
"The market is rising today, but without real conviction. ...Flows from investors remain thin," said Jean-Louis Cussac, head of Paris-based firm Perceval Finance.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (Reporting by Sudip Kar-Gupta, editing by John Stonestreet)