Our total debt increased from $2,836 million as at 31 December 2016 to $3,239 million as at 31 December 2017, partially due to the appreciation of the Rouble against the US dollar. Net debt increased by $209 million to $2,688 million.
PAO TMK placed two bond issues on the Moscow Exchange during 2017 for a total of RUB 15 billion. In April, the Company placed a RUB 5 billion ten-year bond with a 9.75% coupon and a put option exercisable in three years. In June, it placed a RUB 10 billion ten-year bond with a 9.35% coupon and a put option exercisable in four years.
The share of our short-term debt as at the end of 2017 was 18% compared to 9% as at 31 December 2016. In early 2018, TMK fully redeemed its Eurobond issue maturing in January 2018. The nominal value of the redeemed Eurobond was $231 million.
During the reporting year, TMK Group improved its liquidity profile, this included extending maturity dates, mitigating the foreign exchange risk, and decreasing debt financing costs. As at the end of 2017, Rouble-denominated portion of our debt represented 51.5%, the U.S. dollar-denominated portion – 46.2%, and the euro-denominated portion – 2.3% of our total debt. As at 31 December of 2017, our weighted average nominal interest rate was 8.16%, i.e. an 86 bps decrease year-on-year.
S&P Global Ratings (S&P) changed its outlook on TMK’s credit ratings on 27 November 2017 from “Negative” to “Stable” and affirmed the Company’s long-term corporate credit rating at B+. S&P based this revision on stronger TMK’s financial performance driven by the increased drilling, growing demand for tubular products in the US, and relatively low vulnerability of the Russian oil and gas industry to raw material price volatility. Other positive factors were focused efforts by the Company’s management to deleverage and proactive liquidity management.
On 28 February 2018, Moody’s Investors Service (Moody’s) changed the outlook on TMK’s credit rating from “Negative” to “Stable” and affirmed the Company’s B1 corporate family rating. Moody’s based this revision on the much stronger financial and operating performance by TMK’s American division, along with the sustainable Russian division performance in a volatile oil price environment. The updated outlook also includes expectations that TMK will be able to deleverage and maintain adequate liquidity