NEW YORK--(BUSINESS WIRE)--Fitch Ratings has affirmed Mid-Atlantic Corporate Federal Credit Union's (Mid-Atlantic) long-term Issuer Default Rating (IDR) at 'A+' and short-term IDR at 'F1+'. In addition, Fitch has affirmed Mid-Atlantic's Viability rating (VR) at 'bb'-. The Rating Outlook remains Stable. A full list of rating actions follows at the end of this release. KEY RATING DRIVERS - IDRs The affirmation of Mid-Atlantic's IDRs and Stable Outlook reflects Fitch's view that the company will c