UK oil and gas company Serica Energy has rejected a revised merger proposal from smaller Kistos, saying the new offer does not reflect the values of its core assets. Kistos, led by North Sea dealmaker Andrew Austin, said on Monday it had made a revised cash-and-shares offer for Serica at 425 pence a share, an 11 per cent increase from its previous offer and one that values the company at about £1.2bn. Under the terms of the offer, Serica shareholders would receive 0.4 new Kistos shares plus cash of 213p for each of their existing shares.