LONDON, Dec 8 (Reuters) - British digital bank Monzo has completed a fresh funding round valuing the company at $4.5 billion, in a vote of confidence from investors in the loss-making lender. The high-profile neobank, founded in 2015, has received the funding from investors in a round led by Abu Dhabi Growth Fund, a spokesperson for the bank confirmed.The bank has closed the first $475 million injection, with a second close expected within a couple of weeks to take the total raised above $500 million. Monzo has more than 5 million customers but has struggled to turn a profit, with annual losses widening last year as it disclosed it faced a regulatory investigation over a potential breach of anti-money laundering rules. read more The bank said it was making progress improving its finances and had doubled revenues this year as it rolled out more paid-for services, with 300,000 now using paid accounts. Staff numbers have also grown 60% since January this year to 2,100. "This investment means we"ll grow further and faster as we continue on our journey to reinvent banking, and become the one app that sits at the centre of our customers" financial lives," Monzo CEO TS Anil said in a statement. The news was first reported by the Financial Times.