The company's Russia national scale rating was affirmed at "ruAA+".

"The upgrade reflects Gazprom Neft's strengthening stand-alone credit quality due to a more diversified business profile and still-robust financials," S&P credit analyst Yelena Anankina said.

"It also reflects greater clarity about Gazprom Neft's financial policy and about the commitment of Gazprom Neft's 76% parent, OAO Gazprom, to expand its oil activities," she said.