US Stock Market: Citigroup shares slide after upbeat results fail to ease worries over higher costs

Citigroup reported strong second-quarter earnings, driven by trading and investment banking revenues. The bank's net income jumped 45%, surpassing analyst expectations significantly. However, shares declined as investors focused on potential higher expenses ahead. Citigroup maintained its full-year return target, signaling possible weaker second-half profitability. The bank's results align with other major U.S. financial institutions reporting robust profits.