(Reuters) – TransferWise Ltd, the money transfer startup whose investors include entrepreneur Richard Branson and PayPal Holdings Inc founders Peter Thiel and Max Levchin, is seeking to sell a stake in itself in a new fundraising round, people familiar with the matter said on Friday.

The fundraising comes as TransferWise and other startups are shaking up the industry by using new technology to move cash across borders, often at less costly rates than banks and other traditional players.

TransferWise, one of Europe’s best-funded financial technology firms, is seeking to raise up to $300 million, which would value the company at around $4 billion, one of the sources said.

The latest fundraising round is being organised by investment bank Goldman Sachs Group Inc, said the sources, who asked not to be identified because the matter is confidential.

A spokesman for Goldman did not immediately respond to a request for comment.

TransferWise, which was formed by Estonian duo Taavet Hinrikus and Kristo Kaarmann in 2011, has over 4 million customers and transfers more than $4 billion a month, according to its website. It employs more than 1,400 people across 11 offices on four continents.

In January, the company said it was opening an office in Belgium to avoid any potential impact on its business from Brexit.

TransferWise’s last fundraising round came in 2017, when investors including Old Mutual Global Investors and Silicon Valley venture capital firm IVP contributed $280 million, giving TransferWise a valuation at the time of more than $1.6 billion.

The company booked an operating profit of 9.5 million pounds ($12.4 million) over the 12-month period ending in March 2018 on 117 million pounds in revenue.