UK managing director Jon Sharpe, sales and marketing director Ethan Segal and client services director Matt Gorzkowski are understood to have left itraffic to set up their own digital agency.
A BA spokesperson said: "We are continuing to work with itraffic and have no immediate plans to review the account."
Last month itraffic lost Hilton International's digital business to fledgling agency Web Liquid, set up by former itraffic directors David Shiell and Alain Portmann.
In response, Andy Hobsbawm, managing director of itraffic's parent, Agency.com Europe, has been appointed to the role of acting managing director for itraffic London. David Eastman, head of client services at Agency.com, will take over Hobsbawm's role for an interim period.
"Agency.com is exceptionally committed to the interactive marketing space and itraffic is an extremely well-established agency in London with a strong retained client base," said Hobsbawm.
"The transition between management teams will be handled with minimum disruption to our clients. Confidence and morale among employees remains high."
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