JPMorgan's dealmaking fees slipped by 3% in the third quarter, kicking off what is expected to be a tough period for Wall Street banks amid an ongoing slump in M&A and equity capital markets activity.

Investment banking fees at the Wall Street bank were $1.7bn in the third quarter, down by 3% on the same period last year. JPMorgan leads its rivals in the dealmaking league tables — and has gained market share this year — but its results show that the deal drought continues to squeeze fees.