Nestle has been making and selling a few General Mills cereals in Europe for about 15 years now. The deal started in the early 90s, when my wife was employed by General Mills. It was never clear just who was playing who. Was General Mills exploiting Nestle and getting a foothold in the European market? Was Nestle plotting to take over General Mills and increase its American market position?

In any case, the projected demand for cereal in Europe never happened, and General Mills bought Pillsbury and became in effect too large to be taken over. What's left is a legacy contract, pretty similar to the way Hershey has the U.S. rights to Nestle's Kit Kat bar.

The contract as it read back in the day was pretty clear that the Nestle versions were to be "substantially identical" to those of the General Mills versions. Nestle and General Mills went to great lengths to source similar ingredients and establish similar manufacturing processes. There were some new localized cereals introduced with flavor profiles more European-friendly, but I'm sure those cereals are long dead.

I would guess those constraints are still in place, so go ahead and buy the cheaper Nestle Cheerios.