Arthur J. Gallagher & Co. CEO Pat Gallagher Jr. shrugged off concerns about the Illinois-based insurance broker's ability to sustain growth through M&As for a longer term, saying that there is a "never-ending" supply of brokers that could potentially be up for grabs.

"The supply and the fragmentation of the market is unquenchable," Gallagher said during a July 26 earnings call. "As far forward as you can see, we will not have a lack of supply."

The comments came after Arthur J. Gallagher announced that it had a number of successful deal closings in the first half of 2018.

CFO Douglas Howell said Arthur J. Gallagher is poised to continue its M&A success in the second half of the year as the insurance broker had about $350 million of available cash on its balance sheet as of June 30 that could be used for future transactions.

"We have a full pipeline of attractive tuck-in merger opportunities," Howell said. "Clearly, we don't expect all of these acquisitions to close. However, we believe we will get our fair share."