Norsk Helikopter is now 100% Bristow (originally 49%) and is now operating as Bristow Norway AS.
CHC Helikopter Service is what it says, CHC.
Norsk Helikopter Service is a new start with a connection to Bond. They are yet to get contracts and aircraft. They are just an AOC at the moment and their name is simply trying to ride off the success of both Norsk Helikopter and Helikopter Service.
TiP