Revolut has raised £387 million at a valuation of £4.2 billion, double the £2 billion price tag attached to rival neobank Monzo.
The investment round was led by Technology Crossover Ventures, an early backer of companies including Airbnb, Netflix and Spotify.
Revolut has been doing the rounds of venture capital firms since October last year, when it was touting a more optimistic $7-$8 billion valuation.
The company has yet to make a profit, reporting a pre-tax loss of £33 million in 2018, more than double the £15m loss a year earlier.
Forrester senior analyst Aurélie L’Hostis, comments: “Revolut has done tremendously well, acquiring users across geographies at lighting speed, and launching a subscription model that made the startup the highest revenue earner among its UK peers. But we're now entering the reality-check phase for challenger banks. Investors will be looking for reassurance that Revolut can achieve sustainable organic growth."
The cash injection will be used to fund the business as it attempts to crack the US market and sustain its growth across Europe.
Revolut founder Nick Storonsky says: “Going forward, our focus is on rolling out banking operations in Europe, increasing the number of people who use Revolut as their daily account, and striving towards profitability.”