text: first merger announcement exxon and mobil oil?   on december 1, 1998, exxon and mobil first announced their intent to merge in a record-setting $80 billion stock swap.  the first recorded announcement of the merger was in "offshore" magazine, volume 58 issue 12, page 119.  on november 30, 1999, exxon and mobil completed their merger, forming exxon mobil corp., the largest public company in the world, mobil shareholders own 30% of the new firm; exxon shareholders, 70%.