Founded in Shanghai, Nitro has offices in London, New York, Melbourne, Brisbane, Moscow and Sao Paulo. Its clients include Mars, Volvo, Nike, RBS and ConAgra.
Chris Clarke, Nitro's founder and chief executive, said: "Everyone on the Nitro global leadership team believes that this is a dream partnership for our clients.
"This partnership combines big creative ideas that capture the imagination of consumers with the digital sophistication to execute and deliver business results.
"We will use technology to liberate the relationship among business, brands and the people who invest in them."
Boston-based Sapient operates two groups -- Sapient Interactive and Sapient Consulting.
Sapient Interactive provides brand and marketing strategy, creative work, and web design and development.
Sapient Consulting provides business and IT strategy, process and systems design, package implementation and custom development.
Alan Herrick, president and chief executive of Sapient, said: "We expect new leaders will emerge to redefine how brands interact with their target consumers.
"This acquisition firmly establishes Sapient's leadership position in this dynamic and fast-growing segment."
The acquisition is subject to certain closing conditions and approvals. It is expected to be completed in early July.
This article was first published on brandrepublic.com