SAO PAULO, March 9 (Reuters) - Brazilian steelmaker Companhia Siderurgica Nacional on Wednesday posted a fourth quarter net income of 1.06 billion reais ($211.48 million), down 73% from a year earlier amid lower domestic steel volumes and prices.

Analysts were expecting the bottom line to come in at 1.85 billion reais, according to a Refinitiv Eikon poll. CSN also reported quarterly net revenue of 10.3 billion reais, below a market forecast of 11.19 billion reais.

CSN said steel and iron ore sales volume fell by 17% and 11% respectively from the same period of 2020.

The steelmaker's adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) hit 3.7 billion reais in the last quarter of 2021, down 21% from a year earlier, while its EBITDA margin dropped 12.1 percentage points to 34.9%.

The company attributed the lower margins in the quarter to a higher volume of rainfall that had a negative impact in its mining and cement segments, and inflationary pressures mainly caused by high cost levels of freight and raw materials.

($1 = 5.0123 reais) (Reporting by Gabriel Araujo and Peter Frontini Editing by Chris Reese)