U.S. regional refined product margins were mixed across all regions in the week ending May 18, Credit Suisse said in a weekly report issued.    
Midwest margins showed the biggest gain, up about 18 percent, while margins in the Rockies region rose by 19 percent.    
West Coast margins fell the most, by about 18 percent. Margins for the Northeast and Gulf Coast regions slipped about 7 percent and 3 percent, respectively.    
Oil prices were lower due to concerns about Europe, the US call to release strategic oil reserves, DOE data which indicated that inventories had risen to the highest level since 1990 and a weaker US economic data, Credit Suisse said in a note.    
WTI prices were down in the week ended May 18, falling by $3.87 per barrel to $93.12 a barrel, it said.    
Source: Reuters