It declined 2.4% or 24 points to 991, according to the Baltic Exchange on Wednesday.
The index has been above 1,000 since 14 August as it enjoyed a steep rise from a recent low of 724 in mid-July.
All the separate bulker size indices were also down.
Daily average earnings for capesizes dropped 6.2% to $9,865, also the lowest since the middle of August.
Panamaxes