UPDATE2: after a week, Carrefour is reportedly doing 1,200 gross adds per day…not bad at all in a fully-penetrated market of 44 million people. (via Xataka)

UPDATE: A mysterious comment by “in the know” asks us to “watch this space”, implying that Wal-Mart may indeed planning to enter the mobile market. If this is true, it would be really big news. Of course, so far it’s just an anonymous comment left on a blog…

The big news in Spain is that Carrefour, the second largest retailer in the world after Wal-Mart, is launching an MVNO this week.

It will easily be the cheapest prepaid offer on the market (15 cents/minute to call any phone on any operator, 12 cents/sms). A cheap contract offer is coming early next year.

In the UK, Tesco, the world’s third largest retailer after Wal-Mart, has had a very nice success with its Tesco Mobile MVNO.

…all this begs the question: why doesn’t Wal-Mart itself do an MVNO in the US?