S&P also affirmed the ratings outlook at stable, Petrol said in a filing with the Ljubljana Stock Exchange on Monday.
In August, Petrol Group said its consolidated net profit rose 4% on the year to 40.7 million euro ($44.9 million) in the first half of 2019.
Petrol Group's sales revenue totalled 2.7 billion euro in the first six months of 2019, up 15% on the year, the company said at the time.
Petrol's closed 0.28% higher at 356 euro on Monday.
($ = 0.90675 euro)