(Updates with stock price, additional background throughout)

 
   DOW JONES NEWSWIRES 
 

Tesoro Corp. (TSO) plans to offer $300 million in 10-year senior unsecured notes, with the refiner planning to use the proceeds for things including debt refinancing.

Numerous companies have been selling stock and/or notes to pay off or refinancing debt as investors show increased interest in such securities. Tesoro as of March 31 had $1.55 billion in debt.

The sale comes as oil and refined-product demand falls amid the recession. Some refineries in the U.S. may close permanently as a result of the ongoing weakness.

The U.S.'s third-largest refiner by capacity said last month it swung to a first-quarter profit, though revenues, prices and demand continued to slump.

Tesoro shares recently were up 0.9% at $17.67. The stock has more than doubled since November.

-By Tess Stynes, Dow Jones Newswires; 201-938-2473; tess.stynes@dowjones.com