* FTSEurofirst 300 up 0.4 pct, Euro STOXX 50 up 0.5 pct
* Brent drops through 'pain threshold' of $80 a barrel
* Earnings season strong but lack of revenue growth nags
By Blaise Robinson
PARIS, Nov 13 (Reuters) - European stocks rose on Thursday, reversing a small portion of the previous day's slide, with some reassuring corporate results offsetting weak economic data from China.
Shares in energy companies slipped, however, as Brent crude oil fell below $80 a barrel and hit a four-year low, with Seadrill, Saipem and TGS down 0.5 percent to 1.9 percent.
"$80 is the pain threshold," said Alexandre Baradez, chief market analyst at IG France.
"Below that, a lot of the oil majors' projects are not profitable and a lot of oil-producing countries start to have serious budget issues. It's also a problem for the euro zone because it drags down inflation."
The prospect of belt-tightening by energy majors as oil prices plunge has hurt the oil services sector, with some shares plummeting between 30 percent and 65 percent in recent months.
At 1155 GMT, the FTSEurofirst 300 index of top European shares was up 0.4 percent at 1,348.84 points, after losing 1.1 percent on Wednesday. The index has held in a tight range since late October.
Iliad gained 4.8 percent on Thursday after the French telecom group said it added more mobile subscribers than analysts expected in the third quarter.
KBC rose 6.7 percent after the Belgian financial group posted a better-than-expected net profit, while Portuguese retailer Jeronimo Martins surged 10 percent after reassuring investors that it still expects strong sales growth and profitability at its leading unit, Poland's Biedronka.
With the European earnings season nearing an end, results overall have been strong, with 60 percent of companies meeting or beating profit forecasts, according to StarMine data.
In absolute terms, however, while profits are up 13 percent, revenues are up a meagre 0.8 percent, highlighting that Europe's earnings rebound has mostly come from cost-cutting.
"While corporate activity is pretty much stable, operating margins are hitting a peak. People shouldn't expect a further rise in the margins if there's no growth in revenue," said Bruno Fine, head of Roche-Brune Asset Management.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (Additional reporting by Alexandre Boksenbaum-Granier; Editing by Ruth Pitchford)