TORONTO (Reuters) - Goldman Sachs' ( GS ) trading revenue will probably slip 10% in the third quarter because of sluggish conditions last month, its CEO David Solomon said on Monday.

Given "a more challenging macro environment, particularly in the month of August, that business is trending down close to 10%," Solomon told investors at a financial conference in New York.

The Wall Street giant's profit more than doubled in the second quarter as dealmaking rebounded, with debt underwriting and fixed-income trading performing particularly well.