However, the loss was partially mitigated by higher net fund-based and non-fund-based income.
RHB said its revenue fell 6.9% to RM12.59bil from RM13.53bil in 2019.
The board of directors has proposed a final dividend of 7.65 sen per share under a dividend reinvestment plan, which if approved would bring total FY2020 dividend payout to 17.65 sen per share, or 34.8% payout ratio.
In FY20, RHB said net fund-based income grew 6.3% year-on-year (y-y-o-y) to RM5.27bil due to proactive funding cost management, which dropped 23.8% y-o-y.
This was also supported by a 28.3% CASA growth and the redemption of certain capital instruments over the course of 2019 and 2020.
Net interest margin dropped to 2.06% versus 2.12% recorded in 2019, mainly owing to the 125bps overnight policy rate cuts.
Non-fund-based income rose 11.2% to RM2.34bil, owing mainly to higher net trading and investment income, brokerage income and insurance underwriting surplus.
Operating expenses remained constant y-o-y at RM3.39bil while cost-to-income ratio improved to 47.1% compared wtih 48% a year earlier.
"The group remained prudent and continued to set aside pre-emptive provisions to cater for potential adverse impact to asset quality brought about by the COVID-19 pandemic.
"As a result, ECL increased significantly from RM275.8 million in the previous year to RM1,145.1 million. Full year credit charge ratio rose to 0.58% compared with 0.18% last year," it said.
In 4QFY20, RHB's net profit fell 29.47% as compared to RM621.01mil in the previous corresponding quarter.
Revenue was 10.04% lower at RM3.08bil compared with RM3.42bil in the previous comparative quarter.
Elaborating on the financial balance sheet and capital position, RHB said total assets grew 5.3% y-o-y to RM271.1bil as at Dec 31, 2020.
Common Equity Tier-1 and total capital ratio stood at 16.19% and 18.37% respectively.
Gross loans and financing were up 5.6% since December 2019 to RM186.1bil, mainly supported by growth in mortgage, auto finance, SME and Singapore.
Domestic loans and financing grew 4.5% y-o-y.
Gross impaired loans were RM3.2bil with a gross impaired loans ratio of 1.71% compared with RM3.5bil and 1.97% respectively as at Dec 31, 2019.
Loan loss coverage ratio for the Group, excluding regulatory reserves, was well above 100% at 119.7% as at end-December 2020.
"The Group revisited our business plan and reprioritised our FIT22 strategic initiatives, allowing us to quickly adapt to the changing business environment and shifts in customer behaviour brought about by the pandemic.
"Given the challenging operating environment, we continued to be innovative in our approach, while exercising vigilance by building our provisions and enhancing prudent risk management practices and at the same time maintaining a strong capital and liquidity base," said group managing director Datuk Khairussaleh Ramli.
He added that the group will continue to ensure the health and safety of its employees as well as the well-being and sustainability of its customers' businesses.
Meanwhile, the bank will continue to offer support to its customers via the targeted payment assistance programme, which will run to June 30, 2021.