The shift is likely to see the £1m UK business move out of Abbott Mead Vickers BBDO into TBWA\London.
Masterfoods has been realigning its global brands into TBWA; the agency now oversees about half of its portfolio. The food giant shifted its ad accounts for Twix, Starburst and Galaxy, worth £12m, from Grey to TBWA in late-2004.
The US review included BBDO and independent New York agency Nitro.
Snickers recently lost head of brand Jenny Williams to Nokia, where she will head its UK marketing.