"The rating withdrawal reflects a lack of information on the company's consolidated financial position and its strategy," the company said in a statement.
According to S&P, over the last three years Tatneft has substantially delayed publishing its audited U.S. GAAP accounts, with 2004 accounts published in June 2006, and the 2005 financials not yet available.
S&P also highlighted Tatneft's unclear relationship with the government of the Republic of Tatarstan, which controls the company, and a lack of information on company's $4.8-billion Nizhnekamsk refinery project.
However, S&P said the withdrawal did not necessarily indicate a deterioration of the company's credit quality but reflected impossibility to determine Tatneft's current credit standing and evaluate creditors' risks.
"As a result of the withdrawal, Tatneft will no longer be subject to Standard & Poor's surveillance," the statement said.
Based in the city of Almetyevsk, Tatneft is the only Russian company listed in both London and New York. The company said earlier this month it had produced over 12.7 million tons (about 94 million bbl) of crude in January-June 2006, representing a 0.15% year-on-year increase.
The company posted a net profit according to Russian Accounting Standards of 23.4 billion rubles (about $872 mln) for the first half of 2006, up 45% on the same period of last year.