Investment bank Goldman Sachs Group (GS) posted a profit of $1.93 billion, or $3.70 a share, for the second quarter – an increase from income of $962 million, or $1.78 a share, in the same quarter of 2012.

The company’s net revenue reached $8.6 billion, up from $6.6 billion a year earlier.

Goldman’s CEO Lloyd Blankfein credited improving economic conditions for driving U.S. client activity.

Net revenues in the institutional client services segment alone hit $4.31 billion, up 11% from the second quarter and a 16% rise from last year.

That jump is due to higher net revenues from currencies, credit products and commodities. However, the surge in revenue was somewhat offset by lower net revenues in mortgages and lower net revenue interest rate products.

"Although fixed income, currencies and commodities client execution operated in a generally favorable environment during the first half of the quarter, market conditions across products became more challenging during the latter part of the quarter, as interest rates and market volatility increased," Goldman wrote in its report.