The UK Web Shows Now study from Futurescape examined 50 online television, mobile and feature film productions made in the past year and found that Endemol, Conker and Big Balls account for more than 30% of the market.
Conker Media, owned by All3Media's Lime Pictures, has produced four programmes in the past year including 'Runners' the show-within-a-show launched by 'Hollyoaks' on Channel 4, to be shown next year.
Big Balls' most recent project is Nokia's 'Someone's Else's Phone' campaign.
Colin Donald, director at Futurescape, said: "What is particularly striking is how film production company Big Balls has successfully executed a business and creative strategy of expanding out from music videos and television commercials into online comedy and drama, where it competes on equal terms with much larger and well-established indies."
The study also showed that independent studios, such as Belfast-based Be Entertainment and Greenroom Entertainment have gained a competitive advantage by making interactive and creative programmes, which have lead to repeat commissions.
Be Entertainment is due to produce season three of Bebo teen drama 'Sofia's Diary' in 2009, and Greenroom has made a new student comedy 'Fresh!' for BBC Switch and sitcom 'Terryvision', commissioned by BBC Wales.
Other up-and-coming studios include Monkey Kingdom, Hatrick, World of Wonder and Pure Grass Films, of which Endemol has a 40% stake.
The market study also found an emerging trend of producers bypassing broadcasters, instead working towards online advertiser-funded productions.
One example is 'Katie & Co', a romantic comedy featuring Jacob's Creek wine, made by Big Balls for Pernod Ricard, which runs on the Mail Online site and is promoted in The Mail on Sunday.
The study said: "This trend demonstrates the growing interest by major brands in directly reaching online viewers with their own original programming, via internet distribution deals that exclude broadcasters in favour of rival media owners."