HONG KONG (S&P Global Ratings) May 2, 2018--S&P Global Ratings today said that its ratings on Korea-based refining and petrochemical producer SK Innovation Co. Ltd. (SKI; BBB+/Stable/--) are unaffected by the company's announcement that it will buy back around Korean won (KRW) 1 trillion worth of its shares. We expect SKI to fund the share buyback mostly with cash at hand (about KRW4.2 trillion as of December 2017), and expect the impact on its financials to be contained with debt-to-EBITDA weakening by 0.2x to about 1.0x, based on our 2018 adjusted EBITDA projection. We note, however, that any additional material investments by SKI could further pressure the company's financial risk profile.