With 90% of the shares, Couche Tard can force the remaining 10% to sell at the offer price. With less than 90%, the company has a minority shareholder that can be a bit of a problem from time to time. Minority shareholders have protected rights that doesn't allow the majority shareholder to do as he pleases. For example, the majority shaeholder might want to sell the company at a certain price to a certain party. The minority shareholders have to agree in a majority fashion. It gets complicated.