Rockbox, a subsidiary of Clear Channel International, has held the contract for more than five years. Whichever company wins the contract will be the recommended supplier of poster sites. The NUS currently has 137 sites at its union buildings, which, it claims, are used by more than 5m students in the UK.
The Union plans to write to all the UK's outdoor media companies and said that final tendering dates and requirements will be released within the next eight weeks.
A spokesperson for the NUS said: "We have worked with CCI/Rockbox for many years. Over that time, it has been a solid partnership but we now feel it is better for our member unions if this contract goes to tender.
"We already tender many points of access to the student market and have found that this is the most productive way to support our member unions."
The preferred bidder will be decided by committee, with NUS Ents and NUSLL, the companies servicing the NUS, all having to agree on the supplier.
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