TMK, Russia\'s largest producer of steel pipes for the energy sector, saw its fourth quarter 2011 net profit skyrocket 405 percent quarter-on-quarter to $106 million, the firm said in a statement on Friday. Revenue stayed almost flat in October-December 2011 at $1.603 billion comparing with the third quarter. The company increased its sales by three percent to 1,017 tons of pipes in the last three months of 2011. Gross margin stood at $331 million, 10 percent increase year-on-year. Adjusted Earnings Before Interest, Taxation, Depreciation, Amortization (EBITDA) grew 10 percent to $223 million, while EBITDA margin went up to 14 percent from 13 percent. Net debt slipped $60 million to $3.552 billion as of December 31, 2011, while net debt/EBITDA ratio amounted to 3.4:1 as of the end of last December. As for the whole 2011, TMK\'s net profit soared 270 percent to $385 million comparing with 2010, while revenue grew 21 percent to $6.754 billion. \"TMK confirms its positive outlook on the pipe market for 2012 and expects a slight increase in sales volumes and further improvement in the product mix compared to 2011. E&P budgets of Russian oil companies are continuing to grow in 2012 driven by continued high oil prices which should support demand for OCTG and line pipe,\" TMK said in a statement.