CPA firms are increasing their email marketing, according to a new report.

The report, from Thomson Reuters’ BizActions and PDI Global brands, analyzed data from over 20 million email communications sent out through the BizActions email system every year. The majority of them are email newsletters. In 2012, BizActions and PDI Global accounting firm clients sent over 22 million e-newsletters and email radars, also known as email blasts. That represented a slight increase over the quantity sent out in 2011.

According to a benchmark study of over 1,000 brands by the email marketer Silverpop, the average national open rate was 19.9 percent in 2012. Thomson Reuters said its accounting firm clients achieved similar results, showing average open rates across all contact types (excluding email radars) of 23.3 percent in both 2012 and 2011. When email radar rates are calculated in with newsletter open rates, the averages go up even further. One BizActions accounting firm client, Weiss & Company LLP, achieved the highest newsletter open rate of 35.4 percent.

While 55 percent of marketing professionals agree that email marketing is the most effective marketing tactic, according to data from MarketProfs, there can be drawbacks. For example, 69.7 percent of email users instantly delete an email that doesn’t render well when received on their mobile device, according to eMarketer. According to another survey, by StrongMail, 56 percent of businesses plan to increase their email marketing budget.

Shorter subject lines generally outperform lengthier ones, the report noted. It recommended that marketers avoid using any subject line longer than 49 characters. According to one recent report, from Informz, subject lines with fewer than 10 characters yielded the highest open rates at 51 percent.

Thomson Reuters’ report is available for CPA firms to download here. “The report reinforces that, despite the rise of social media, email continues to be the most effective and profitable marketing tool for accounting firms of all sizes,” said Keith Haurie, vice president of emerging products at Thomson Reuters, in a statement. “It’s effective in building awareness, nurturing leads, acquiring new clients, improving retention, and driving revenue, and frequently serves as the foundation for inbound marketing strategies as well. This report gives CPA firms benchmarks to gauge their own successes and includes recommendations to help them improve their marketing’s return on investment.”

In a recent survey StrongMail’s “2013 Marketing Trends Survey”, 9 out of 10 business owners said they plan to maintain or increase marketing budgets this year. Two-thirds of respondents plan to integrate social media and email and 46 percent intend to increase spending on email marketing to drive growth of their corporate social media channels.

The report tracks and compares 2011 and 2012 trends in accounting firm email click activity, open rates, and other key metrics and breaks down the results by contact type, geographic region, firm size, and distribution day and time. The data for the report is based on more than 20 million email messages compiled from more than 18,000 BizActions client accounts in the U.S.

“As emphasized in the report, clients and prospects place a higher value on information that is tailored specifically to them, their needs, and their businesses,” said Haurie. “Targeted content marketing helps CPA firms engage their contacts by providing the information they want and need, which provides more opportunities for the firm to grow its business.”