Interesting, Yes, in terms of hustling, kikuyus, somalis and bahindis have it. Gusii are coming up - but mostly transport and real estate sector. The other kabilas are just not yet there. Kalenjin are into trucking and farming - at micro-level - although the Moi elite have big business... For example, Jack chebett, Stabex, run Uganda petrol, his petrol stations are anywhere close to 100...but at mirco-level..not there.
On fuel business, Go to Pipeline depot in Nairobi, this is where you find fuel hustlers. These people started of milking trucks and adulterating fuel with paraffin. Some of them have graduated to owning multinational branded petrol stations. Most of all this people hail from Muranga thanks to their original Godfather Thayu(Astrol). Yes Somalis have serious marketshare in the fuel business but so do kikuyus. The difference is kikuyus are more operating individually while Somalis invest more as a group. Most of the outlets selling clothes in Nairobi are kiuk owned and they import from china, turkey etc via Eastleign. On eateries the likes of kilimnjaro , the somalis have overpaid for those outlets and the only people who frequent those restaurants are somalis. The point is somalis are doing well but not at the expense of other tribes. The market changed and expanded where other tribes also have their marketshare.