Brunswick Group and Sard Verbinnen & Co were the top M&A PR advisors in the U.S. during the first quarter of 2013 based on deal value and volume, respectively.

mergermarketResearch firm mergermarket reports that Brunswick advised 16 transactions worth nearly $76.4B during the period. That included representing Berkshire Hathaway and 3G Capital Partners in the quarter's largest global deal, the $27B purchase of HJ Heinz, as well as Silver Lake Partners and Michael Dell in the No. 2 U.S. transaction for Q1 -- the duo's $20B bid for Dell.

Sard Verbinnen handled 23 deals worth $31.4B during Q1, including Dell in the Silver Lake/Michael Dell bid along with MSLGroup and Kekst and Company.

The third largest deal of the quarter was the American Airlines-US Airways merger. Kekst (21 deals, $31.2B) and MSLGroup counseled American partner AMR Corp., while Joele Frank, Wilkinson Brimmer Katcher (13 deals, $22.1B) guided US Airways.

Abernathy MacGregor Group (14, $25B) and FTI Consulting (16, $5.4B) were also top five U.S. advisors by value and volume.

Global M&A fell 7.6% in Q1 compared with the same period of 2012, the slowest opening quarter in ten years, according to mergermarket. But U.S. deal value surpassed Q1 of 2012 by a whopping 38%, even though the number of deals fell from 922 to 727.

Brunswick, which worked the three largest global transactions during Q1, also led the global deal tables for PR advisors for Q1, handling 36 transactions worth $86.6B. FTI Consulting was the volume leader with 47 deals worth $16.4B.

In the No. 2 global deal, Brunswick advised Liberty Global in its $22B purchase of Virgin Media, the latter represented by Powerscourt and Tavistock Communications.