Maersk and Hamburg Sud are the most reliable container shipping lines as of 2015 according to industry analyst Sealntel. Many large shipping lines have seen a decline in schedule reliability since 2013 due to port congestion. Maersk earned a reliability score of 83.7 percent. Hamburg Sud's score was 82.2 percent.
Line operators encounter most problems on the main east-west trades as adverse weather conditions in both Europe and the east coast of the United States affect schedule integrity. Sealntel states that as of 2014 the largest problem for carriers and shippers is port congestion in Los Angeles and Long Beach in California.