The affirmation was made in its release copied to the Ghana News Agency on Friday.

The rating provides a significant boost for the Bank at a time when it is discussing a substantial general capital increase to finance its strategy and activities over the next few years.

Fitch Ratings is one of the leading global providers of credit ratings, commentary and research.

The agency upgraded the intrinsic assessment to 'AA' from the previous 'AA-'driven by an improvement in Fitch's assessment of the Bank's business environment.

The Bank's 'AAA' support from its shareholders was based on Fitch's forecasts that the Bank's net debt will be fully covered by callable capital from 'AAA' rated member countries by 2021.

The projection assumes shareholder approval of an increase in subscribed capital from 2020, and lending growth averaging seven per cent year on year in 2019-2021.

Other key points from the Fitch rating include the Bank's solvency assessment of 'AA' primarily reflecting its 'strong' capitalization with its equity to asset and guarantees ratio remaining within the 'strong' range.

Fitch's usable capital to risk-weighted assets (FRA) ratio, newly introduced, was just below the threshold for an 'excellent assessment (35 per cent) at end of 2018 and is likely to be 'excellent in 2019.

The release said overall risk is rated as 'low', with risk management policies seen as conservative and assessed as 'excellent'.

It said concentration risk was considered 'low' and has benefited from the Exchange Exposure Agreement with other development finance organisations.

The release said equity participation was expected to remain below five per cent of the banking portfolio by 2021, in line with the internal limit of 15 per cent of risk capital.

The liquidity assessment is 'AAA' and the quality of liquid assets is 'excellent

The Bank's business environment now translates into no negative adjustment (from a one notch negative adjustment previously) to the improved intrinsic rating, which reflects a stronger assessment of the bank's strategy to 'medium' risk from 'high' risk.

As the Fitch rating states, the process for a General Capital Increase (GCI-VII) is expected to be completed by end of 2019, including a final agreement on its amount.

Dr Akinwumi Adesina, the President of the AfDB, welcomed the assessment saying, "I am delighted by the affirmation of the AAA rating as well as the accompanying explanations, which clearly explain the solid and comprehensive reasons for the overall improvements in the intrinsic rating, as well as the 'extraordinary support' we receive from our shareholders."

"It is a massive boost for the Bank to be encouraged so strongly in the year of the General Capital Increase and with so much hard evidence provided."

He said "it is also a tribute to all our stakeholders, partners, and those who have been working at and with the Bank during this past year.

 "Fitch's rating is not just about our credit; it speaks volumes for the Bank's solid achievements, consistent strategy, development impact, leadership, and overall direction."