Castore, the British sportswear brand partnered by tennis player Sir Andy Murray, is hoping to raise about $200m as it raises the stakes in its battle with Adidas and Nike.

City sources say Manchester-based Castore has appointed Rothschild to engage with investors.

The business mainly sells its products online and positions itself as a quality alternative to established global rivals.

It has a number of kit supply deals including a five-year contract with Rangers worth £20m. English Premier League football teams Newcastle United and Wolverhampton Wanderers are other clients, and it is building a presence in other sports such as cricket, golf, rugby union and Formula One.

Three-times Grand Slam winner Sir Andy modelled a fashion range with Castore after becoming a shareholder in the company in 2019.

The Scot and Castore agreed a partnership with his AMC clothing brand which in 2021 became the official apparel partner for Tennis Scotland in a three year deal.

Other shareholders include the billionaire Issa brothers, who jointly own Asda and the petrol forecourts giant EG Group.

Castore was valued at £750m after its most recent debt financing, which took place last autumn.

Bankers believe Castore is a candidate for a stock market flotation, according to Sky News which reported the latest fund-raising plan.