In 1876 the SMN started a cooperation with her competitor the Stoomvaart Maatschappij Java (SMJ). On 31 May 1876 the shareholders of SMJ approved the lease of all the ships of SMJ to SMN. That same day the SMN held her regular shareholders meeting, and proposed the cooperation with the SMJ. The SMN shareholders were far less enthusiastic but in the end they also agreed. Most of the ships of the SMJ would be used for cargo, except for "SS Celebes".