Drug company Merck Ltd today posted a 58.37 per cent rise in net profit at Rs 20.05 crore for the fourth quarter ended December 31, 2012.

The company had posted a net profit of Rs 12.66 crore for the same period of previous fiscal.

Net sales of the company rose to Rs 161.17 crore for the third quarter, as against Rs 126.56 crore during the same period of previous fiscal, Merck said in a BSE filing.

For the year ended December 31, 2012, the company posted a net profit of Rs 78.40 crore against Rs 63.68 crore for the previous year, it said.

Net sales of the company rose to Rs 658.07 crore for the year ended December 31, 2012, as compared to Rs 557.57 crore in 2011, it added.

Shares of Merck today closed at Rs 661.35 on the BSE, up 0.91 per cent from their previous close.