Oil Companies: Mobil Corp. reported first-quarter profit...

Oil Companies: Mobil Corp. reported first-quarter profit of $710 million, a 78% increase over the year-ago period. The Fairfax, Va.-based company had sales of $16.6 billion, compared to $15 billion a year ago. The company cited its international operations for most of the earnings increase. Because of improved refinery margins, Amoco Corp. said its first-quarter net income climbed 6% over 1990 after allowing for a onetime benefit in accounting changes for income tax purposes. It reported earnings of $803 million on sales of $7.3 billion, compared to $466 million on revenue of $7.1 billion for the year-ago period. Chicago-based Amoco said $311 million in profit was the result of cumulative effects of changes in accounting. Occidental Petroleum Corp. said its first-quarter earnings rose 26% over last year, reflecting higher profit in its oil and national gas transmission divisions. The Los Angeles-based company said its net income was $136 million on sales of $5.3 billion, compared to $108 million on sales of $5.2 billion last year.