The Swanson Group, a tax, accounting and consulting firm based in Westbrook, has acquired Howgate & Harmon, a South Portland accounting firm with four full-time employees, the company said Tuesday.

The acquisition will bring Swanson Group to 17 employees with projected annual revenue more than $2 million and a clientele of about 2,000 Maine businesses and residents, the company said in a news release. The company said it will pay the seller an annual percentage of each retained client’s overall value, which is standard for acquisitions in the accounting industry, but it declined to disclose the percentage.

“When I started this firm, I knew that I wanted to create a diverse team and build a strong business,” Swanson Group principal Tabitha Swanson said in the release. “It’s important that our growth mirrors the changing needs of Maine’s small business community – and with the new tax laws, there are more questions than ever.”

In 2015, Swanson Group acquired two other accounting firms, the tax portion of Connolly Financial in Yarmouth and Kierstead & Fox of Westbrook. In all three acquisitions, the firms’ owners were looking toward future retirement, the release said. With each acquisition, all employees of the acquired firm retained their jobs, it said.

Swanson founded the firm in 2012 and has plans to acquire more accounting firms in the near future, according to the release. Swanson Group is renovating an aging building on Main Street in Westbrook to accommodate the new staff.