Rockbridge Growth Equity has acquired ProSites Inc., a provider of comprehensive online marketing solutions, from The Riverside Co.

Founded in 2003, ProSites serves more than 14,000 clients in the dental, medical, financial and accounting practices. It specializes in website design and hosting, reputation management, search engine optimization, pay-per-click advertising and practice communication software.

"ProSites is our latest investment in the digital marketing space," Rockbridge Managing Partner Kevin Prokop said in a statement. "Dave Rutan and his team have built a market-leading company with a broad portfolio of products that serve local community professionals.  We look forward to working with Dave and the company to accelerate the company's growth, increase the range of services it provides and target new verticals that can benefit from ProSites' services."

ProSites' growth has helped to position it as a leader in the marketing and workflow solutions sector.

The ProSites acquisition is the second investment that Detroit-based Rockbridge has announced in the past month. Earlier in October, Rockbridge announced an investment in White Glove, a digital marketing company that provides a comprehensive approach to marketing and seminar planning for professionals in the finance, insurance, legal and real estate industries.

ProSites will join Rockbridge and the Rock Family of Companies which includes other high-growth businesses such as Quicken Loans, Gas Station TV, Connect America and Bedrock, a full-service real estate firm specializing in acquiring, leasing, financing, developing and managing commercial and residential space.

ProSites was advised by JEGI, a leading independent investment bank focused on media, marketing, information and technology. Honigman served as a legal counsel to Rockbridge. Terms of the agreement were not disclosed.