Metro Bank shares tumble again amid fresh worries about its finances

Shares in Metro Bank have fallen again as investors grow increasingly nervous and impatient for news of a promised injection of new money to help strengthen its finances.

The price was down 15% at one stage on Thursday, before closing 8% lower. The value of the 66-branch bank has plunged 85% over the last year.

Metro Bank is trying to raise £350m to help boost the capital in the bank after it revealed in January it had miscalculated how much shock-absorbing capital it needed to support a number of business loans.

That news in February sparked a 40% fall in the shares, and the price has nearly halved again since then. At the time, chief executive Craig Donaldson said there were "absolutely no question marks" over the bank's future.

At its recent earnings announcement, Metro Bank further revealed that some of its larger business customers had begun taking money out of the bank.

I have written before about the doubts in the minds of investors and regulators about the bank's business model.

Sources close to the bank insist that the new money would be raised as promised by the end of June and that the share sale had been underwritten by the banks arranging the sale.

Metro Bank has been under close supervision by regulator the Prudential Regulation Authority after the capital miscalculation.

• Metro Bank opened its first branch in London's Holborn in 2010 in the wake of the financial crisis

• It was the first High Street bank to open in the UK in more than 100 years

• It is one of so-called challenger banks to the big High Street names, and opens seven days a week

• Founder Vernon Hill shook up the US banking scene in 1973 when, aged 26, he founded Commerce Bank one branch

• When he sold Commerce Bank in 2007 for $8.5bn, it had 440 branches

A bank spokesman told the BBC that after a fall in March, deposits returned to growth in April. However, some investors told the BBC it thought Metro Bank was taking too long to raise new cash and that the longer it took, the harder it would become.

When companies need to raise new money quickly, new shares are usually offered at a steep discount to the current market price.

When shares are falling this quickly, it becomes difficult to determine what that is. Metro Bank's current total value is £515m - meaning that selling £350m in new shares would see current investors see well over half their stake in the bank wiped out.

Retail customer deposits are protected up to a value of £85,000 by the Financial Services Compensation Scheme.

The bank said that despite the steep fall in share price, customer deposits were not at risk.