Eric Stein, managing director of online advertising network DoubleClick UK is the company to return to the States.
Stein joined in January 1999 to replace Andy Mitchell, who left to head up AltaVista UK, which was a DoubleClick client at the time.
DoubleClick has been thwarted recently by a succession of job cuts. In December, it laid off 150 people from its worldwide workforce of 2,100.
At the time Stein said he believed DoubleClick held a dominant position within the internet ad sales sector, and stressed jobs at senior management level would not be affected.
Stein's departure comes as rival company Engage cuts its international workforce by half. Fifteen per cent of UK employees will also be laid off.
Last week also saw 24/7 Europe chief executive Gordon Simpson admit the board would welcome a takeover of the internet ad sales house.