UPDATE 1-Sunoco posts 1st-qtr loss on weak refining margins

(Adds segment earnings, background outlook)

NEW YORK, April 30 (Reuters) - U.S. refiner Sunoco Inc (SUN.N: Quote, Profile, Research) posted a first-quarter net loss on Wednesday from a year-earlier profit on weak margins for gasoline.

The company posted a net loss of $59 million, or 50 cents a share, compared with a profit of $175 million, or $1.44 a share, last year.

Revenue rose to $12.81 billion from $9.31 billion last year.

The company said its refining and supply business lost $123 million. Margins to produce gasoline have plummeted as refiners have struggled to push through higher crude costs to customers. First-quarter gasoline prices rose only 33 percent year over year in the U.S. -- less than half crude's rise.

The company said margins for distillate products in the second quarter remain very strong and gasoline margins are beginning to improve.

It expects crude runs and production levels to be between 90 and 95 percent of capacity in the second quarter, up from around 85 percent last quarter.

Sunoco shares closed at $46.41 on the New York Stock Exchange on Wednesday. (Reporting by Michael Erman; editing by Carol Bishopric)