Union Bectu has told the BBC that it plans to ballot members at BBC Technology about taking industrial action over the sale.
The union said it has seen a secret plan for redundancies that was drawn up by BBC managers last year and has been shown to the two shortlisted bidders.
BBC chief technology officer John Varney would not rule out the possibility of compulsory redundancies following the sale but said IT staff would have a better opportunity to find alternative work with the successful bidder.
Because BBC Technology is being sold rather than outsourced, staff will not be covered by Tupe legislation, which protects workers' terms and conditions when transferring to a new employer. However, Varney said the BBC required shortlisted bidders to demonstrate that they can provide Tupe protection to staff.