Sky News has learnt Monzo is in advanced negotiations to raise in the region of $50m by issuing new shares to the Asian city-state's Government Investment Corporation (GIC).

City sources said the top-up to the neobank's recent funding round could be announced in the coming weeks.

If successfully completed, the raise will add Singapore to an increasingly eclectic group of shareholders in one of the UK's most successful start-ups.

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Monzo, which was founded in 2015 and now boasts more than nine million customers, is now profitable, and has diversified into investments and instant access savings accounts.

Last month, it confirmed a Sky News report that it was raising more than £300m by selling shares to a syndicate of investors led by Capital G, the independent growth fund of Alphabet, Google's parent company.

One insider said the recruitment of Capital G as an investor had been a factor in attracting money from GIC, which ranks among the world's biggest state-backed investment funds.

Monzo, which is now the most highly valued digital bank in Britain, also ranks as the seventh-biggest bank in Britain by number of customers.

The company is among a new generation of banks which have emerged since the last financial crisis and begun to accumulate a significant share of the UK retail banking market.

Rivals include Starling Bank, which last week named a permanent chief executive to replace its founder, Anne Boden.

Revolut, which was valued at $33bn (£26.5bn) in a funding round in 2021, has yet to receive a UK banking licence despite months of talks with regulators.

Monzo has recovered spectacularly from a difficult period two years ago, when it emerged the City watchdog was investigating it for potential breaches of anti-money laundering and financial crime rules.

It has historically been loss-making in common with most start-ups, reporting a loss of £116m in the year to the end of February, but is expected to be profitable this year - a major milestone for a standalone digital bank.

Its latest fundraising is expected to be the last before Monzo unveils an initial public offering, in which it would sell shares to the public.

It recently revamped its corporate structure as it pursues an international expansion strategy that will serve as the prelude to a stock market listing.

Monzo Bank Holding Group was established to avoid the company facing punitive capital treatment by British regulators as it launches in new overseas markets.

Existing Monzo investors include the Chinese group Tencent, Passion Capital, Accel and General Catalyst.

Monzo is run by TS Anil, its chief executive, and chaired by Gary Hoffman, one of Britain's most prominent bank executives.

"With backing from global investors, we have the rocket fuel to go after our ambitions harder and faster, building Monzo into the one app that sits at the centre of our customers' financial lives."

Monzo declined to comment, while GIC could not be reached for comment.