The problem in the proposed merger of Japan's three biggest shipping companies (Nippon Yusen, Mitsui O.S.K. Lines and Kawasaki Kisen Kaisha) is, that synergy number looks ambitious - and if it falls short, the players haven't really improved their position much, says Bloomberg. A business is rarely more than the sum of its parts. That's a problem for anyone hoping that combining Japan's big three container-shipping lines will produce a stronger company and the world's sixth-biggest line. The joint venture would see savings of more than $1bln a year. With a fleet of 256 container vessels, the proposed business would hold about 7% of the world shipping market. The promised 110 billion yen in annual synergies -- or 27.5 billion a quarter -- would change things dramatically.