Positive or negative to have a bandwidth > cohererance bandwidth, why?

Hi,

I am trying to learn about signal propagation and path losses. When I am reading about multipath losses, the coherence bandwidth comes up often. But I get mixed answers about it would be positive or negative to have a signal bandwidth, broader than the coherence bandwidth. I also do not understand the reason for it.

Could someone help me understand if it is positive or negative to have a bandwidth broader than the cohererance bandwidth, and why, in regards of multipath loss.

Best regards.