No further details were immediately available.
Podgorica-based Mercator-Mex, set up in 2007, has a capital of 6,001,681 euro ($8,850,318), according to data from its parent's website.
Outside Slovenia, the Mercator group (www.mercator.si) is present in Serbia, Croatia, Bulgaria, Montenegro and Bosnia. The group has announced plans to enter Albania by the end of 2009 and to also set foot on the markets in Macedonia and Kosovo.
No trading data on Mercator shares was available from the LJSE website by 1226 GMT on Thursday. They closed down 2.68% at an average price of 172.41 euro on Wednesday.
($=0.6722 euro)