i guess horizontal
hm good question
since in real biz structure i would say it has limits so i go vertical bcause each store owner only erans from thier location there is no downline
so it cant go horizontal and then down like an MLM biz would be
even this some franchises are so large and world wide they can be thought of as MLM models !
Horizontal. Walmart's strength is based on latitudinal expansion and coverage.