The first-quarter earnings cycle for the world's largest investment banks closed this week with aggregate revenue up 14 percent year-on-year, led by fixed-income trading and a long-awaited recovery in equity capital markets.

JPMorgan Chase set the tone, reporting net income of $14.8 billion on revenue of $44 billion. CEO Jamie Dimon attributed the result to "breadth of franchise" and warned that loan-loss provisions would likely rise modestly through the second half.

European banks delivered their strongest quarter in over a decade. BNP Paribas, Santander and UBS all reported double-digit return on tangible equity, with wealth management franchises particularly buoyant on the back of strong equity market performance.

The single common warning across the cycle was the trajectory of consumer credit. Credit-card delinquencies in the United States and the United Kingdom are now at their highest level since 2011, and several lenders have begun to tighten underwriting criteria for subprime borrowers.