Marketing company Taptica International said it had agreed to acquire rival RhythmOne for around £135m in shares.
Taptica offered 28 of its shares for every 33 RhythmOne shares held.
It also announced that the combined group would launch a $15m buy back immediately following completion of the offer.
'The enlarged group is expected to create one of the leading video advertising platforms in the US,' Taptica chairman Tim Weller said.
'It will be able to offer a comprehensive technology platform to its customers with a full demand side and supply side offering to create interesting global opportunities.'
'This, coupled with the enlarged group's global scale of operation, is important to retaining and gaining customers and will enable it to compete with other market leaders in the video advertising space.'
(LON:RTHM) RhythmOne PLC share price was +7.5p at 177.9p
(LON:TAP) Taptica International Ltd share price was +18p at 216p