Final answer:
The greatest bargaining power in the shipping industry is generally held by companies that ship the greatest amount of freight, which enables economies of scale and better negotiations for lower rates.
Step-by-step explanation:
The greatest bargaining power in the shipping industry, leading to the lowest rates, is typically held by companies that have the greatest amount of freight being shipped. Larger freight volumes often allow for more efficient space utilization on cargo ships, better negotiating leverage due to higher business value to carriers, and the economies of scale in cost savings. Additionally, containerization has greatly economized shipping by making it easier to transport goods across various modes of transportation, thereby reducing shipping costs per unit and increasing competition in the manufacturing sector.