According to The Mirror, research on the secondary ticket market published by Which? has revealed enough information to warrant an investigation by the Competition and Markets Authority in Great Britain.

The Which? research found that as much as a quarter of all ticket inventory for major music, theatre, and sporting events will end up on secondary ticket sites like Viagogo, StubHub, GetMeIn!, and Seatwave. GetMeIn! and Seatwave are owned by primary ticketing giant Ticketmaster.

Findings show that 26% of tickets for comedian Jack Whitehall’s Eventim Apollo show ended up on these four secondary sites, as did 17% of tickets for Lady Gaga at the O2 Arena in London and 15% of tickets for the first night of the BBC Proms at the Royal Albert Hall.

Buy Sell and Go with confidence at StubHub

Upon the publication of this research, a StubHub spokeperson said it should be noted that sellers tend to list inventory on multiple platforms, which would greatly skew the accuracy of these numbers.

“According to our own figures, only 1% of tickets compared to the total venue capacity are listed for sale on StubHub, a much smaller number than the amount of tickets which are typically not put on public sale.”

Which? reported that tickets for the first night of the BBC Proms with an original cost of £38 (about $50) were found to have a mark-up of 279% on StubHub (£144 or about $190) and 300% on GetMeIn! (£152 or about $200).

StubHub again defended their practices, adding that prices tend to drop as the event nears.

“For example, Jack Whitehall tickets for this weekend were selling on StubHub for £19.50 (about $25), £10 (about $13) less than the original cost.”

While opinions on primary versus secondary inventory and dynamic pricing are subjective, the Competition and Markets Authority (CMA) is investigating suspected breaches of consumer protection law in the secondary ticket market.

The Which? study found that half of people (49%) who bought tickets from Viagogo, GetMeIn!, Seatwave and StubHub thought that they were purchasing from official sellers. Ten percent said that upon arrival at the event, their seat or area was not as described.

Which? managing director of home products and services, Alex Neill, said: “People are finding themselves having to buy tickets through secondary sites more and more, and yet many struggle to find the basic information required by law. There needs to be more transparency within the secondary ticketing industry and the competition authorities must take strong action against those who aren’t playing by the rules.”

Which? is an independent, not-for-profit organization that aims “to make things better for consumers, and to raise standards across the board” through testing goods and services and publishing the results.