Jeronimo Martins rises as JPM double upgrades stock

** J.P.Morgan double upgrades Jeronimo Martins JMT to "overweight" from "underweight", saying the shares are due a re-rating after a recent decline in the shares

** The Portuguese food retailer's JMT shares rise around 3.6%, cutting YTD losses to 14.2%; they are among the best performers on the pan-European STOXX 600 SXXP

** JPM says that after a "rather sound" Q1, it is assuming underlying volume acceleration at the group's Polish unit Biedronka, and more muted margin contraction in the year

** "We estimate Biedronka LFLs and Margins to trough into the second and third quarter to become an inflection point," it says

** JPM adds that Portugal and Colombia, where the trough has become evident, also contribute to the overall earnings upgrade, as it hikes its estimates by 5-10%

** It says Jeronimo and Belgium's Colruyt COLR have more room to manoeuvre with gross margins than peers due to their lower prices, and thus more control over earnings

** Jeronomo Martins' shares are on track for their best day since late October if gains hold