British cross-border money transfer firm TransferWise is mulling to raise up to $300m by selling stake in a new financing round, Reuters reported citing undisclosed sources.

The deal would value the company at $4bn, a source told the news agency.

Previously, Richard Branson and PayPal founders Peter Thiel and Max Levchin invested in the company, which uses a new technology for cross-border funds transfer.

Launched in 2011 by Taavet Hinrikus and Kristo Kaarmann, TransferWise has more than four million customers and a transfer volume of more than $4bn per month.

It operates 11 offices with a total of more than 1,400 employees. In January this year, the company announced plans to establish an office in Belgium to support its business following Brexit.

The company raised £65m funding in November last year from NatWest, JP Morgan and LHV Bank to support its existing and future working capital needs.

Prior to this, the company secured $280m financing in 2017 from Old Mutual Global Investors and venture capital firm IVP, among others.

According to Reuters, the valuation of TransferWise at the time was more than $1.6bn.

TransferWise annual revenues increased by 75% in the year to 31 March 2018 to £117m ($151m), from £66m. The company’s net profit after tax was £6.2m for the year to 31 March 2018.