SAN FRANCISCO — M&A lawyers and bankers expect 2013 to be a very good year. An annual survey by the Brunswick Group found 97 percent of respondents expect an increase in North American deal activity in the coming year, up from 48 percent in 2012.

However, specific drivers of deal activity are more muted, the survey found, with no single force standing out. Brunswick, a financial public relations firm, surveyed 100 M&A lawyers and bankers for its annual report, released Wednesday.