Mobil Oil. The red 'O' represents the beginning of the second word 'O(b)il'.
In 1999 Mobil and Exxon merged into ExxonMobil.
The font for this logotype is a specially modified version of Avant Garde. The distinctive Pegasus (flying horse) logo was used by Mobil's original company, the Magnolia Petroleum Company.
In the '80s and '90s a stylized pegasus logo was used together with the Mobil logotype here and appeared as a red horse in a circle.