AgBank's net profit for October-December fell to 31.17 billion yuan ($4.64 billion) from 32.95 billion yuan a year ago, according to Thomson Reuters calculations based on the company's annual figures.

That was below the 32.50 billion yuan profit estimate from analysts, according to Refinitiv SmartEstimate. SmartEstimates give more weight to recent estimates by analysts who are more consistently accurate.

Net interest margin - the difference between interest paid and earned and a key gauge of bank profitability - was 2.33 percent at end-December, versus 2.35 percent at end-June and 2.28 percent at the end of 2017.

AgBank said its non-performing loan ratio edged down to 1.59 percent at end-2018 from 1.60 percent at the end of September.

Full-year net profit rose 5.1 percent to 202.78 billion yuan from 192.96 billion yuan in 2017.

China's economic growth slowed to a 28-year low in 2018, and signs of further cooling are stoking worries about risks to the world economy and weighing on profits for firms ranging from Apple Inc to big car makers.

To spur growth, Beijing has introduced a series of policy measures that seek to ease the financing and operational difficulties of private firms and small businesses, and injected liquidity into the financial system through successive reserve requirement ratio reductions to boost credit creation.

(Reporting By Shu Zhang and Julie Zhu; Editing by Muralikumar Anantharaman)