The world-famous guitar maker Fender and four leading keyboard manufacturers are at the centre of a price fixing investigation after “dawn raids” were carried out at their British offices.

In total, four keyboard companies and the American guitar giant were targeted by staff from the Competition and Markets Authority (CMA).

Although the companies have not been officially named, The Sunday Telegraph understands they include Yamaha, one of the biggest musical instrument manufacturers in the world, Roland, Korg, Casio and Fender.

The CMA website states that five separate “initial investigations” have been launched into “suspected breaches of competition law by various parties”. It adds that inquiries “relate to alleged anti-competitive agreements and/or concerted practices in relation to musical instruments and equipment”, adding that it is focusing on “suspected anti-competitive agreements”.

The investigations all began in April, when CMA officers arrived unannounced at the five offices. Its officers can enter a business without needing a warrant and demand documents.

However, the CMA stresses that the investigations are “at an early stage and no assumptions should be made that competition law has been infringed”.