Nortel Networks, the telecom products and broadband network company, is reviewing its dollars 50m (pounds 34m) global advertising business currently held by the True North network.
The review is being overseen by Nortel in the US, which has hired an unnamed consultancy to handle the review process.
The business is currently run globally by Bozell and Temerlin McClain in the US, with European creative adapted by Delaney Lund Knox Warren.
Media planning is handled in the UK by BJK&E, with Claydon Heeley Jones Mason overseeing the below-the-line work. It is not known whether these are affected by the review. Nortel spent pounds 1.6m on advertising in the UK this year.
The company is best known for its TV ads which use The Beatles' Come Together, with the tagline 'What do you want the internet to be?'
The ads, which broke in the UK last year, were designed to highlight the wider range of internet and broadband services that the company was able to offer following its acquisition of Bay Networks in 1998.