Even as global uncertainties heightened in 2018, we were steadfast in serving the needs of our customers and in growing our regional franchise. Our performance during the year reflected this discipline.
UOB achieved another new high in net profit, up 18 per cent to more than $4 billion. Our net interest income grew 13 per cent year on year, driven by broad-based loan growth and higher net interest margin. Net interest margin increased five basis points to 1.82 per cent, in line with the rising interest rate environment.
Net fee and commission income increased five per cent to $1.97 billion, driven by the strong performance in loan-related, credit card, trade-related and fund management fees. Other non-interest income declined 20 per cent to $930 million mainly due to unrealised mark-to-market on investment securities and lower gains from the sale of investment securities.
Our core businesses continued to deliver strong income growth. Total income for Group Retail rose four per cent to $3.95 billion, supported by healthy volume growth and improved deposit margin. Group Wholesale Banking reported an income growth of 11 per cent to $3.94 billion, led by double-digit loan growth and broad-based increase in fee and customer treasury income. Total income for Global Markets grew six per cent to $465 million, driven by favourable movements in foreign exchange and rates.
The Group continued to invest in our talent and technology to improve our productivity, our products and services and our customer experience and to reap the productivity benefits of digitalisation. As a result, total expenses increased seven per cent to $4 billion. The cost-to-income ratio for the year rose marginally to 43.9 per cent.
Our balance sheet remained strong and keeping it efficient remains a priority. The return on risk-weighted assets increased to 1.93 per cent compared with 1.63 per cent a year ago, driven by our record earnings.
Our asset quality was stable. Total credit costs on loans eased to 16 basis points, reflecting the fairly benign credit environment for the most of 2018, as well as low residual risks from the oil and gas and shipping sectors. Non-performing loan ratio improved further to 1.5 per cent from 1.8 per cent a year ago. Non-performing assets reserve coverage remained adequate at 87 per cent, or 202 per cent after taking collateral into account.
The Group’s funding position remained strong, with our loan-to-deposit ratio at a healthy 88 per cent as at end 2018. Our Singapore dollar and all-currency liquidity coverage ratios of 209 per cent and 135 per cent respectively as well as net stable funding ratio of 107 per cent were well above regulatory requirements. Against last year, gross loans grew 11 per cent to $262 billion while deposits grew seven per cent to $293 billion. We continued to manage actively and to optimise our asset-liability mix.
In 2018, we established our inaugural Global Medium Term Note Programme which enabled us to tap the US onshore market under Rule 144A of the US Securities Act for the first time. For more details on issuances in 2018, please refer to the Investors section of the Report.
Capital-wise, as at 31 December 2018, our Common Equity Tier 1 CAR remained strong at 13.9 per cent. Our leverage ratio of 7.6 per cent was more than double the regulatory minimum requirement. The Group remains well capitalised to navigate the macro uncertainties ahead.
In 2018, we maintained our position as one of the world’s strongest banks, with a rating of ‘Aa1’ by Moody’s and ‘AA-‘ from both Standard & Poor’s and Fitch Ratings.