50 Billa grocery stores had been purchased by Conad, another Italian retail store, and the switch-over is scheduled to be completed over the weekend, with stores reopening on Monday, February 23, under the new name.
There's been no word at all as to whether all of the Billa stores in the area are included in this group of 50, and no word on whether Conad will have the same hours as Billa. (I hope so!) Monday morning when I discover more, I'll update this post. Just about the only information has been these big posters in the vaporetto stops, and a sign in the Billa stores announcing that you need to use up any store points you have before the change over occurs.
So- if you are returning to Venice anytime in the near future after having been away for some time, be prepared to be greeted by the new kid in town: Conad.

