The Baltic Exchange's main sea freight index, which tracks rates for dry-bulk carriers, hit a more than two-year high on Wednesday as rates for panamax vessels rose.
The overall index, which factors in rates for capesize, panamax, supramax and handysize shipping vessels, was up 5 points at 1,338 points, its highest level since Nov. 11, 2014.
The panamax index was up 40 points or 3.1 percent, at 1,346 points.
Average daily earnings for panamaxes, which usually carry coal or grain cargoes of about 60,000 to 70,000 tonnes, rose $318 to $10,805.
The capesize index paused after surging to the highest level in more than 2 years in the previous session. It fell 10 points to 2,755 points.
Average daily earnings for capesizes, which typically transport 150,000-tonne cargoes such as iron ore and coal, slipped $97 to $20,560. Capesize rates have more than doubled so far this month.
An increase in iron ore and coal shipments to China, owing to the country's curbs on production, and ramping up of output in Australia and Brazil have helped average spot rates and the Baltic index, analysts said.
Iron ore shipments account for around a third of seaborne volumes on the larger capesizes and iron ore price movements are a key factor for dry freight.
Among smaller vessels, the supramax index fell 8 points to 885 points, while the handysize index rose 3 points to 538 points.
(Reporting By Nallur Sethuraman in Bengaluru)