Clifford Chance and Allen & Overy are advising as RBS becomes the first U.K. financial institution to issue a "social bond", which aims to address regional inequality and promote economic growth in the U.K.'s most deprived areas.

The issuance, which has raised about £650 million ($839 million), is the first issued under RBS's new framework and is, according to a statement by Clifford Chance, the first "exclusively social bond" issued by a U.K. financial institution.

Clifford Chance is advising RBS with a team led by capital markets partner Paul Deakins.

Meanwhile, A&O acted for the underwriters, with partner Theo Trayhurn leading, according to a person with knowledge of the issuance.

In a statement, RBS said the bond is linked to the bank's £2.5 billion ($3.2 billion) of existing lending to small and medium-sized businesses.

"As the first bond to be issued under our new framework, it paves the way for future issuances in support of our green, social and sustainability ambitions, as well as helping to diversify the bank's investor base," said RBS chief executive Alison Rose.

Earlier this week, Clifford Chance won a mandate advising the U.K. government on its second-ever issue of an Islamic bond.

A&O recently advised Santander bank on the issuance of its 'end-to-end' blockchain bond worth $20 million in September.