The shares opened at 302 pence each and traded as high as 308.75 pence by 8:24 a.m.

The bank had priced its initial public offering (IPO) at 290 pence a share, giving it a market capitalisation of 725 million pounds.

The listing comes just weeks after that of another British banking newcomer, Aldermore (>> Aldermore Group PLC). Shares in Aldermore have risen more than 20 percent since then.

Shawbrook was founded in 2011, one of several "challenger banks" to emerge since the financial crisis as the government and customers alike sought alternatives to Britain's "Big Five" lenders - Lloyds (>> Lloyds Banking Group PLC), HSBC (>> HSBC Holdings plc), Royal Bank of Scotland (>> Royal Bank of Scotland Group plc), Barclays (>> Barclays PLC) and Santander UK (>> Banco Santander, S.A.).

The bank's total lending reached more than 2.3 billion pounds in 2014. It is backed by private equity fund Pollen Street Capital, previously known as SOF Investments, which was spun out of Royal Bank of Scotland in 2013.

Shawbrook had initially set a price range of between 255 and 305 pence a share for its IPO. The deal will raise 90 million pounds through the sale of 75 million shares, which the company said it would use to support its capital ratios and fund growth.

BoA Merrill Lynch (>> Bank of America Corp) and Goldman Sachs (>> Goldman Sachs Group Inc) led the listing. Macquarie Capital was joint bookrunner, while Keefe, Bruyette & Woods acted as co-lead manager.

(Reporting By Freya Berry; Editing by Pravin Char)