The ratings on Korea-based SK Innovation Co. Ltd. (BBB/Stable/--) reflect the company's leading market position, integrated business portfolio, and flexible financial policy. Factors that constrain the ratings are the economic cycles of the company's main businesses, its vulnerability to fluctuations in oil and currency prices, and rising uncertainty about regulatory pressure in the domestic petroleum market. SK Innovation is Korea's leading oil refining and marketing (R&M) company, with about 35% of the domestic petroleum market. Given this strong position, we expect it to maintain stable profitability in the domestic market in line with an outlook for solid refining margins in the region. Firm petroleum demand and closures of refining facilities by less competitive players will help maintain strong refining margins