** Zabka's ZAB.WA shares jump around 10% to the top of Warsaw's blue-chip index .WIG20 after the Polish convenience store chain reported better-than-expected Q2 earnings
** Q2 adjusted core earnings (EBITDA) came in at 1.06 billion zlotys ($286.84 million) vs an estimate of 1.02 billion seen in a Reuters poll
** Zabka also raised its store opening forecast for 2025 to more than 1,300 stores, up from an earlier plan to open more than 1,100
** "Solid results for the second quarter, an upgraded outlook for 2025, and good prospects for the coming quarters should trigger a positive market reaction," Piotr Bogusz, analyst from Erste Group says in a note
** "We see some potential to raise our adjusted EBITDA forecast for this year," says Grzegorz Kujawski from Trigon
** If gains hold the stock will see its biggest one-day rise on record
($1 = 3.7731 zlotys)
(Reporting by Marta Maciag)
((Marta.Maciag@thomsonreuters.com))