The present article analyses the present status of the container liner shipping and its market concentration. The forming of strategic alliances is considered in detail against the other forms of market cooperation. The specifics of strategic alliances in liner shipping is outlined, the latter being one of the drivers for operational and strategic efficiency of liner services. The results show that there has been a significant increase of market concentration as from 2014. The formation of strategic alliances ensures for lower operational costs although leading to, in the short-run, overcapacity and increased internal competition. From a long-term perspective, the formation of strategic alliances will lead to increased market concentration and, eventually, to more stable shipping markets and decreased competition.