The two companies have been in talks for some time with Acxiom Corporation making a cash tender offer for all Digital Impact shares, which is expected to include $20m (£10.6m) in cash.
The agreement follows Digital Impact's decision to turn down a $2-a-share unsolicited offer from InfoUSA, with Acxiom acquiring Digital Impact for $3.50 (£1.86) a share in cash, giving the company a significant presence in the growing digital technology marketplace.
The acquisition will provide the customers of the San Mateo-headquartered Digital Impact with access to Acxiom's data management and expertise, for a combination of technologies, services, people and clients in the direct marketing industry.
Charles Morgan, Acxiom company leader, said: "With the growing demand and spend in this category, Acxiom believes this is an ideal time to enter this space in a leadership position."
William Park, chairman and CEO of Digital Impact, said: "Digital Impact's employees will continue to provide world-class service as part of a larger and more diversified company that Fortune magazine has recognised five times as one of 'The 100 best companies to work for in America'."
Founded in 1997, Digital Impact has around 280 staff with offices in New York, London, Singapore and Bend, Oregon.
It develops campaigns across multiple media channels, including personalised email, targeted websites, web ads, search engines and direct mail.
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