In a statement announcing a new Takeover Panel deadline of 28 November, the companies said “substantial progress has been made and the two parties are at an advanced stage of discussions”.
The firms had been due to announce their intentions by the end of 31 October.
AG Barr, best known for the Irn-Bru fizzy orange drink, first made a move to merge with larger rival Britvic last month, which has been reeling from a product recall and poor weather in the UK.
Earlier this month, Britvic said the recall of its popular Robinsons Fruit Shoot children’s drink in the UK over faulty bottle caps impacted revenue growth by about two per cent.
Wayne Brown, analyst at Canaccord Genuity, said: “Whilst we retain our view that the merger is of significant benefits to both parties, this second extension will stoke fears that the merger is more complicated than most had initially anticipated.”
“This should come as no real surprise considering the underlying financial challenges that Britvic faces set against the conservative and pragmatic nature of the AG Barr board,” he added.