Financial planning and advisory services have helped fuel an increase in revenues at CPA firms, according to a new study by the American Institute of CPAs and Moss Adams.

The survey found an average financial planning practice size of $460,000 among the 431 CPA firms that responded, with an average yearly growth rate of 34.9 percent between 2004 and 2006. Respondents anticipated a 20.6 percent increase in assets under management in 2007.

Thirty-eight percent of the firms are affiliated with an independent broker/dealer, while 28 percent are affiliated with an insurance agency/broker, 47 percent are listed as a registered investment advisor, and 26 percent have no affiliation.

Despite the positive trends, CPA financial planners and advisors still face challenges. "Even with their higher levels of growth, the majority of practices are currently smaller than those in the broader industry, which may place them at a competitive disadvantage," said the report.

Some CPAs seem to have hit a few stumbling blocks in their financial planning practices, the survey also found. On top of growth-related challenges, 52 percent of the respondents who keep financial planning and advisory services in-house are challenged with successfully integrating these services with their broader CPA firm business.