London- and Toronto-listed Centamin PLC said Dec. 18 that prospective buyer Endeavour Mining Corp. refused to share vital information that would help determine its value unless Centamin agreed to extend the deadline for lodging a firm offer.

Endeavour has until Dec. 31 to announce whether it will formally pursue or abandon its takeover bid for Centamin, whose board had rejected the Africa-focused gold producer's C$2.52 billion all-share offer.

The companies had agreed to undertake reciprocal due diligence to assess the feasibility of a merger. But Centamin said Endeavour declined to provide the information the takeover target requested, including the bidder's financial model.

Centamin's board said it is "disappointed" over Endeavour's refusal to engage while urging the latter to enter into reciprocal due diligence without delay.

Peel Hunt analysts said that without a tactical shift from either company, talks are unlikely to progress, Reuters reported the same day, citing a note.

Centamin said it will determine whether to seek an extension of the "put up or shut up" deadline following its review of any information from Endeavour. The company's board also advised shareholders to take no action on Endeavour's offer.