Big breweries are investing in their own artisan-style beers, while supermarkets are expanding their own brands, said City law firm RPC.
Mega-breweries are also gaining greater market share by acquiring brands as well as launching their own, research found.
Jeremy Drew, head of retail at RPC, said: "Global drinks giants are also now launching their own artisan brands to capitalise on the growing craft beer market and to compete with the threat of independent breweries.
"In the past, mega-breweries may have placed greater emphasis on consolidating their current range."
