Originally Posted by GVA
How did you guess

Aside from the VS codeshares, I'm not aware of any big CO codes flying across the atlantic. CO does codeshare with NW across the Pacific (e.g., SFO-NRT), but since they don't serve many of these routes with their own metal, CO tends not to be competitive on fares on those routes (I guess they're focusing their attention on routes they actually serve).