Global merger and acquisition deals declined in the second quarter from the previous three months, fueling concern that executives are hesitant to put cash-rich balance sheets to work, Bloomberg reported.

Announced M&A deals totaled $611 billion in the second quarter, a 23 percent decline from the first quarter, according to preliminary data from Thomson Reuters. Measured by deal value, it marked the first sequential quarterly decline in activity in more than a year.

“There is still an upward trend in M&A momentum, but I think we are in a rough patch right now,” said Jeff Raich, managing director of Los Angles-based Moelis & Co. He said the pace of deals is slowing as volatility in equity markets, uncertain economies and sovereign debt problems dampen CEO confidence.

Deal totals for the first six months of 2011 look comparatively robust. Worldwide M&A has risen 40 percent so far this year to $1.4 trillion, the best first half since 2008.

“Cash balances are still high, and debt capital is still available at historically low costs,” said Patrick Ramsey, co-head of Americas M&A for Bank of America Merrill Lynch.