** Shares of SIG Group AG SIGNC.S jump over 11% after the Swiss paper packaging company published better-than-expected first quarter results
** Q1 revenue at constant currency was stable at 714.3 million euros ($835.30 million), against expectations of a fall
** Vontobel analysts say the results beat expectations "across the board". They cite favourable timing in Asia and pre-orders in the Middle East as driving factors
** "Operational measures start to bear fruit," they say, but flag rising raw material and logistics costs as a new challenge
** SIG Group shares are on track for their biggest one-day gain since March 2020
($1 = 0.8551 euros)
(Reporting by Simon Ferdinand Eibach)
((Simonferdinand.eibach@thomsonreuters.com))