Agencies have been approached about a pitch for the business, with ISBA advising O2 in the initial stages of the process.
The account is currently handled by TMP, but the telecoms brand is believed to be talking to several agencies ahead of a pitch.
VCCP, the incumbent on the main O2 brand account, is unaffected by the business-to-business review. ZenithOptimedia, O2's media agency, is also unaffected.
An O2 spokesman said: "We are currently in the process of running a request for proposal for marketing campaigns within the B2B area."