NEW YORK--(BUSINESS WIRE)--Fitch Ratings has upgraded the rating on the city of Greenville (NC) Greenville Utilities Commission's (GUC) $38.4 million of outstanding combined enterprise system revenue bonds series 2001, 2008A and 2008B to 'AA-' from 'A+'. The Rating Outlook is Stable. SECURITY The bonds are special obligations of the city of Greenville and are secured solely by a pledge of all net receipts of the combined enterprise system, which is composed of the electric, water, wastewater an