Credit Suisse says second-quarter net profit plunged 84 percent as the Swiss bank pressed on with a restructuring and revaluation of its investment banking portfolio.

The bank, which is being restructured by CEO Tidjane Thiam, still returned to profitability after a loss-making first quarter and amid expectations among analysts for a second-quarter loss.

Net income was 170 million Swiss francs ($172 million), compared to analysts' expectations for a loss of 201 million francs and versus a profit of 1.05 billion francs a year earlier. Revenues fell 27 percent to 5.11 billion.

Thiam and Chairman Urs Rohner said in a letter published with Thursday's results that they remain "cautious" about the second half of the year amid geopolitical and macroeconomic uncertainties, such as the British vote to leave the European Union.