* Ceconomy shares gain almost 5 pct
(Adds details, background):
BERLIN (Reuters) - Shares in Metro AG (B4B.DE) jumped on Monday as Ceconomy (CECG.DE) announced it may join family-owned Haniel [FHANI.UL] in selling a stake in the German retailer to an investor group led by Czech billionaire Daniel Kretinsky. Ceconomy, the consumer electronics retailer that split off from Metro last year, said on Monday it was in talks to sell most of its 10 percent stake in Metro to investor group EP Investment, represented by Kretinsky.