International credit ratings agency Fitch Ratings has awarded a top investment-grade rating to the Brics-owned New Development Bank, citing its low risk profile and robust capitalisation.

A long-term issuer default rating of AA+ with a stable outlook, with a short-term rating also at AA+, is the second-highest ranking on the Fitch scale.

Fitch, one of the three largest global credit ratings agencies, said on Friday it considered the bank’s capitalisation as "excellent" and its risk profile as "low".

"Fitch assesses NDB’s risk-management policies as strong, mainly driven by self-imposed prudential rules that the bank abides by, primarily on the capitalisation and liquidity fronts," Fitch said.

But it also cautioned against a "concentration risk", saying the "relatively limited number of countries NDB expects to be operating in results in a ‘high’ level of concentration risk".

Fitch expected the risk to subside as the bank diversifies and expands its membership in future.

The multilateral development bank, formerly the Brics Development Bank, was established four years ago by Brics members Brazil, Russia, India, China and SA.

Fitch said: "NDB was endowed with subscribed paid-in capital of $10bn, of which 38% was already received from the bank's five MS at end-2017.

"On the profitability front, Fitch projects the NDB’s capital generation to average 2.4% per year by 2027, in line with our expectations that the NDB will benefit from relatively low borrowing costs."

It said the bank’s dynamic lending growth would be partly offset by the disbursements of subscribed paid-in capital over the next four years.

That, with its profitability metrics, translated into an equity-to-asset ratio of above 25% over the 10-year forecast period.

New Development Bank president Kundapur Vaman Kamath said the rating was "an exceptional achievement for a multilateral development bank fully owned and led by developing countries".

The rating enabled the bank to access capital from global financial markets at attractive rates, while supporting the development agendas of its members in the areas of infrastructure and sustainable development, he said.

At the 10th Brics Summit hosted by SA in Johannesburg in July, Kamath said the bank had to date approved 23 projects worth $5.7bn in member countries.

The bank was considering lending to other developing nations as well as evolving its financing structure to include co-lending and investment on a case-by-case basis with other development banks.