Maitland was £2.5bn ahead of Hudson Sandler, largely due to retained work for SAB Miller on its £2.9bn acquisition of Grupo Empresarial Bavaria from Grupo Santo Domingo.
Brunswick re-entered the table in third place after handling US media relations for SAB Miller on the deal.
Finsbury moved up four places to fourth position. The firm is working for Boots on its £3.1bn acquisition of Alliance Unichem.
Financial Dynamics fell back two places in October, but still managed fifth position for advising Cinven which, with Candover Investments and Permira, is backing Gala Group's £2.1bn acquisition of Coral Eurobet.
Citigate Dewe Rogerson fell two places to eighth but stayed in the top ten as US financial comms adviser for NTL on its £3.4bn acquisition of Telewest.
In an indication of the sharp upturn in M&A activity last month, the top ten advisers worked on more than £85bn worth of deals in
October. This is more than three times the £28.6bn worth of deals worked on by the top ten in September.