It is understood the consortium will offer about pounds 1.18bn, or 248p a share, for the ailing UK group, which effectively put itself up for auction in October.
The proposed bid would trump an offer of about 240p from a rival team led by Paribas, the French bank, and including Germany's Deutsche Bank, the UK's Cinven Group and Danone, the world's top maker of biscuits and dairy products.
Nicola Mallard, an analyst at CCF Charterhouse, said: "With both parties having an industry player, these are two serious contenders." She said if a bidbattle emerged, UB could sell for up to 260p a share.
The acquisition would give Nabisco a leading UK brand as it grows its own biscuit and snacks business. The maker of Oreo cookies and Lifesavers candies bought Favourite Brands International for $475m (pounds 293.2m) last month, making it the biggest US producer of non-chocolate confectionery.Reuse content